Facet joint implants and delivery tools

ABSTRACT

A spinal joint distraction system is disclosed and may include a delivery device, a driver assembly, and an internal actuator, where the driver assembly is adapted to be hold an implant and be sleevably inserted into the delivery device and the internal actuator is adapted to advance an implant distractor to distract the implant, the system also including an implant, a chisel, an injector, a gripping tool, and a dilator set. Several embodiments of an implant are disclosed as well a method of placing an implant.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims priority to: U.S. Provisional ApplicationNo. 61/059,723, which was filed on Jun. 6, 2008 and is entitled SpineDistraction Device; U.S. Provisional Application No. 61/109,776, whichwas filed on Oct. 30, 2008 and is entitled Facet Joint Implants; andU.S. Provisional Application No. 61/169,601, which was filed on Apr. 15,2009 and is entitled Facet Joint Implants and Delivery Tools. Thepresent application also claims priority to, and is acontinuation-in-part (“CIP”) application of, U.S. patent applicationSer. No. 12/317,682, which was filed on Dec. 23, 2008, is entitled FacetJoint Implants and Delivery Tools, and claims priority to ProvisionalApplications 61/059,723 and 61/109,776. The contents of all of theabove-mentioned patent applications are all hereby incorporated byreference herein in their entireties.

FIELD OF THE INVENTION

The following detailed description relates to a device for distractingthe spine. More particularly the description relates to a tool fordistracting a facet joint of the spine and an implant for maintainingthe distracted position of the joint. More particularly the descriptionrelates to an implant that may be used together with a tool to distracta facet joint, the implant remaining in place separated from the tool.In some instances, the implant itself may extract the joint.

BACKGROUND

Chronic back problems cause pain and disability for a large segment ofthe population. Adverse spinal conditions may be characteristic of age.In particular, spinal stenosis (including, but not limited to, central,canal, and lateral stenosis) and facet arthropathy may increase withage. Spinal stenosis results in a reduction of foraminal area (i.e. theavailable space for the passage of nerves and blood vessels), which maycompress cervical nerve roots and cause radicular pain. Both neckextension and ipsilateral rotation, in contrast to neck flexion, mayfurther reduce the foraminal area and contribute to pain, nerve rootcompression, and neural injury.

Cervical disc herniations may be a factor in spinal stenosis and maypredominantly present upper extremity radicular symptoms. In this case,treatment may take the form of closed traction. A number of closedtraction devices are available that alleviate pain by pulling on thehead to increase foraminal height. Cervical disc herniations may also betreated with anterior and posterior surgery. Many of these surgeries areperformed through an anterior approach, which requires a spinal fusion.These surgeries may be expensive and beget additional surgeries due tochanging the biomechanics of the neck. There is a three percentincidence of re-operation after cervical spine surgery. Moreover, thesesurgeries may be highly invasive leading to long recovery times.

There is a need in the art for a device and procedure to increaseforaminal height to reduce radicular symptoms of patients suffering theeffects of spinal stenosis. There is also a need for the device to beadapted to allow for the procedure to be minimally invasive and to avoidmodifying the biomechanics of the spine.

SUMMARY OF THE INVENTION

In one embodiment, a spinal joint distraction system may include adriver assembly including a tubular shaft having a longitudinal axis anda pair of implant holder arms positioned on a distal end of the tubularshaft, where the arms are configured to hold a spinal implant. Inanother embodiment, the driver assembly may also include an implantdistractor positioned along the longitudinal axis near the distal end ofthe tubular shaft, an internal actuator positioned within the tubularshaft and adapted to advance the implant distractor, and a distractorknob adapted to control the internal actuator. In another embodiment,the system may also include a delivery device with a tubular shaft, areceiving assembly positioned on a proximal end of the tubular shaft,and a pair of forks extending from a distal end of the tubular shaft,where the may be adapted to penetrate a facet joint and the deliverydevice may be adapted to slidably receive the driver assembly. In someembodiments, the system may include an implant adapted for holding bythe implant holding arms of the driver assembly. In some otherembodiments, the system may include a chisel with a shaft portion, a tipat a distal end of the shaft, and a head at a proximal end of the shaft,where the delivery device is adapted to receive the chisel, and the headof the chisel is adapted to be tapped by a driving member to insert thetip of the chisel into a facet joint. In still other embodiments, thesystem may include an injector with a cannula with a closed distal endand two exit doors positioned on opposite sides of the distal end, aplunger with a seal positioned within the cannula, a stop disc at aproximal end of the cannula, and a handle positioned on a proximal endof the plunger, where the delivery device is further adapted to receivean injector.

In another embodiment, the internal actuator may be a stand alone deviceinsertable into the driver assembly. In another embodiment, the internalactuator may include a handle and an internal rod, the internal rodbeing adapted to hold an implant distractor, and the handle beingconfigured to release the implant distractor. In another embodiment, thesystem may include a collet positioned on a distal end of the internalrod, the collet adapted to securely hold the implant distractor.

In another embodiment, a spinal distraction implant may include an uppermember and a lower member, the upper and lower member being generallyrectangular and each having a distal edge, a proximal edge, and twoparallel lateral edges, the upper and lower member positioned adjacentand substantially parallel to each other and having an inner surface andan outer surface, the distal edges of the upper and lower memberconnected to each other and the proximal edges adapted to receive animplant distractor, and teeth positioned along the lateral edges of atleast one of the upper or lower member and extending outwardly. Inanother embodiment, the implant may include flanges extendingsubstantially orthogonally from a proximal end of the upper and lowermembers. In some embodiments, the flanges may include openings forreceiving anchors to anchor the implant to a lateral mass of a facetjoint. In another embodiment, the implant may include a truncatedthreaded slot adapted to engage a cross-cut thread feature of an implantdistractor. In another embodiment, the upper and lower members may eachinclude an interlocking scissor feature.

In another embodiment, a method of distracting a facet joint of thespine may include inserting a delivery device to access the facet jointof a patient, inserting a driver assembly holding an implant into thedelivery device, and actuating the driver assembly thereby distractingthe implant.

In another embodiment, a spinal distraction implant may include an uppermember, a lower member, and a proximal member, the upper and lowermembers being generally rectangular and each having a distal edge andtwo parallel lateral edges, the upper and lower members extendinggenerally continuously into each other to form the proximal member, theupper and lower member positioned adjacent and substantially parallel toeach other and having an inner surface and an outer surface, theproximal member being generally perpendicular relative to the upper andlower members, at least one of the upper and lower members furtherincluding threaded slots adapted to receive threads of an implantdistractor and outwardly extending teeth positioned along the lateraledges of at least one of the upper or lower members. In anotherembodiment, the proximal member may include a penetration for receivingan implant distractor.

In another embodiment, a spinal distraction implant may include athreaded bolt with a proximal end terminating in a head, a proximalnon-threaded block positioned along the bolt and abutting the head ofthe bolt, a distal threaded block positioned a distance away from theproximal threaded block, and a plurality of expansion members positionedbetween the proximal and the distal threaded blocks. In one embodiment,the plurality of expansion members may be V-shaped members. In anotherembodiment, the plurality of V-shaped members may be adapted todeformably flatten out and expand laterally when compressed between thedistal and proximal blocks. In another embodiment, the plurality ofexpansion members may be planar plates with slotted holes such that whenfreely positioned on the bolt, the plates are positioned in a skewedposition relative to a longitudinal axis of the bolt. In anotherembodiment, the planar plates may be adapted to engage one another andthus position themselves perpendicular to the bolt when compressedbetween the distal and proximal blocks.

In another embodiment, a spinal distraction implant may include a pairof stacked structures separated by a sloping plane, the structureshaving an engagement surface along the plane including ratchet teeth. Inone embodiment, a first structure of the pair of stacked structuresincreases in thickness in a proximal direction and a second structure ofthe pair of stacked structures increases in thickness in a distaldirection.

In another embodiment, a spinal distraction implant may include agenerally tapered shaft in the form of a screw, the shaft defining alongitudinal axis and having a length, the shaft having threads along anouter surface for engaging articular surfaces of a facet joint. In oneembodiment, the threads may be notched along the length of the implantcreating serrations for cutting into the articular surfaces of a facetjoint. In another embodiment, the threads may include leaf springs forpreventing backing out of the implant. In another embodiment, thethreads may have a T-shaped cross-section. In another embodiment, theimplant may include a relatively broad head with a decorticating featureon a distal surface thereof. In another embodiment, the decorticatingfeature may include tabs projecting distally from the head. In anotherembodiment, the decorticating feature may include spurs. In anotherembodiment, the head may be in the form of a floating collar and be freeto pivot about the longitudinal axis of the implant in a ball and sockettype fashion. In another embodiment, the implant may include a torquelimiting mechanism. In another embodiment, the shaft may include ahollow cavity and take the form of a cone, the cone being made from arelatively malleable material, the implant further including an innercore support member for use when inserting the implant and for removalonce the implant is in place. In still another embodiment, the generallytapered shaft may be a first tapered shaft and the implant may alsoinclude a second generally tapered shaft in the form of a screw wherethe second generally tapered shaft may be positioned adjacent to thefirst generally tapered shaft and have communicative threaded serrationssuch that when one shaft is rotated, the other shaft rotates in theopposite direction. In another embodiment, the implant may include anarm type locking mechanism, the arm being biased in a distal directionsuch that when implanted the arm provides a biasing force to maintainfriction on the threads. In another embodiment, the arm may haveengaging teeth. In another embodiment, the implant may include flapsextending from the head of the shaft and including teeth for engaging alateral mass of a facet joint.

In another embodiment, a spinal distraction implant may include a plateand a orthogonally positioned bumper, the superior aspect of the bumperhaving a rounded surface for opposing the lateral mass of a superiorvertebra, the implant including an anchoring screw for securing theimplant to a lateral mass of a facet joint.

In another embodiment, a spinal distraction implant may include a wedgeinsertable between facet surfaces, the wedge having teeth on at leastone of an anterior and inferior surface thereof. In another embodiment,the implant may also include a diagonally placed anchor screw positionedthrough the implant for advancing into the surface of a facet joint.

In another embodiment, a spinal distraction implant may include ananterior hook, a posterior hook, and a bolt joining the anterior andposterior hook. In another embodiment, the anterior hook may be C-shapedwith a lip and the posterior hook may be S-shaped with a lip, theanterior hook adapted to engage the anterior aspect of the inferiorfacet and the posterior hook adapted to engage the posterior aspect ofthe posterior facet.

In another embodiment, a spinal distraction implant may include aninsert and tabs positioned to extend orthogonally from a proximal end ofthe insert. In one embodiment, the insert may be rectangular and thetabs may have holes for receiving an anchor.

In another embodiment, a spinal distraction implant may include acollapsible diamond shaped structure including two opposing threadedcorners, and two opposing non-threaded corners including pads. Theimplant may also include a bolt threaded through the threaded corners ofthe diamond shaped structure, where actuating the bolt draws thethreaded corners together and extends the non-threaded corners.

In another embodiment, a spinal distraction implant may include an uppermember, a lower member, a hinge connecting the upper member to the lowermember, and a brace member for maintaining the implant in an openposition.

In another embodiment, a spinal distraction implant may include agenerally cylindrically shaped member including at least two sectionsseparated by a slot, the sections connected together at distal ends toform a tip, the member adapted to receive a screw to cause it to expand,and the outer surface of the sections including teeth for engagingarticular surfaces of a facet joint.

In another embodiment, a method of securing a superior verterbra mayinclude applying a force to the superior vertebra to increase theforaminal area between the superior vertebra and an inferior vertebraand placing an angled screw through a superior facet, through a facetcapsule, and into an inferior facet.

In another embodiment, a spinal distraction implant may include acollapsible triangular shaped implant including a central shaft and atleast two springing leaves connected to the distal end of the shaft,extending proximally along the shaft, and biased in a direction to forman arrow shape, where the implant may be collapsed within a tube anddelivered to a site where the tube is removed and the implant is allowedto expand.

In another embodiment, a spinal distraction implant may include a facetspacer plate and screw, wherein the screw may be inserted diagonallythrough a facet surface to engage the facet spacer plate thereby forcingseparation of a facet joint. In another embodiment, the spacer may havea C-shape and the screw may pass through the spacer plate prior toentering the spinal structure.

In another embodiment, a spinal distraction implant may include a firstbracket, second bracket, and a bolt extending between the brackets,where the brackets are adapted to separate when the bolt is turned. Inanother embodiment, the first and second brackets may be adapted to beattached to a lateral mass of a facet joint. In yet another embodiment,the first and second brackets may include a leg adapted to be insertedinto a facet joint.

In another embodiment, a spinal distraction implant may include atriangular shaped wedge, an anchor screw positioned diagonally throughthe wedge, and a malleable flap extending from the wedge including teethfor engaging a lateral mass of a facet joint.

In another embodiment, a spinal distraction implant may include ananchoring plug, an expandable plate, and two external plates, wheresecuring the external plates to a lateral mass of a facet joint andinserting the anchoring plug causes the facet joint to separate.

In another embodiment, a spinal distraction implant may include adelivery system and at least two nitinol hooks, where the hooks may beflattened and inserted with the delivery system and once in place may beallowed to assume their pre-flattened shape.

In another embodiment, a spinal distraction implant may include a hollowscrew sleeve having barbs adapted to be ejected from a retractedposition and a wedge adapted to be inserted in the hollow screw sleeveto eject the barbs.

In another embodiment, a spinal distraction implant may include acollapsible nut positioned over a bolt, the bolt defining a longitudinalaxis, where advancing the bolt may cause the nut to collapse along thelongitudinal axis in an accordion shape, thereby expanding laterally.

In another embodiment, a spinal distraction implant may include acollapsible plate positioned over a bolt, the bolt defining alongitudinal axis, where advancing the bolt causes the plate to collapsealong the longitudinal axis in an accordion shape, thereby expandinglaterally.

In another embodiment, a spinal distraction implant may include a wiresurrounding a block in a helical fashion, the wire adapted to contractand expand laterally when pulled taught or released respectively.

In another embodiment, a spinal distraction implant may include an outerhousing and an internal spring, where the housing may be biased to be ina laterally broad position when the spring is in a neutral position.

In another embodiment, a spinal distraction implant may include a pairof stacked structures separated by a sloping plane and a fastenerpositioned at an angle through the pair of structures thereby preventingrelative movement along the plane.

In another embodiment, a spinal distraction implant may include acollapsible cylinder with side cutouts, the cylinder made from aresilient elastic material.

In another embodiment, a spinal distraction implant may include a distaltip of a delivery tool, where the tip is adapted to distract a facetjoint and detach from the delivery tool.

In another embodiment, a spinal distraction implant may include ahousing, a central gear rotatably positioned within the housing, and twoplates slidably positioned in the housing and positioned opposite oneanother adjacent to the central gear and including teeth for engagingthe gear, where rotating the gear slidably extends the plates beyond anouter surface of the housing in opposite directions.

In another embodiment, a spinal distraction implant may include atriangularly bent plate with a first and second bracket on each side,the first bracket adapted to receive an anchor screw and the secondbracket including teeth for biting into a lateral mass of a facet joint.

In another embodiment, a spinal distraction implant may include arotatable cone with a longitudinal axis including a shoulder with aledge defining a cam surface and an anchor screw, where the shoulder isadapted to be inserted into a facet joint and the implant rotated tocause a superior facet to ride upward along the cam surface and distractthe joint, wherein the screw may be advanced to secure the implant.

In another embodiment, a spinal distraction implant may include ahousing with penetrations for ejection of spikes, internal spikespositioned with the housing and in alignment with the penetrations, andan internal wire routed through the spike positions, where pulling thewire taught forces the spikes from the housing to engage articularsurfaces of a facet joint.

In another embodiment, a spinal distraction implant may include ahousing, a cavity within the housing, penetrations on lateral surfacesof the housing extending from the cavity through the wall of thehousing, spikes positioned to be ejected through the penetrations, thespikes having a beveled inner surface, and a piston having a torpedoshaped distal end positioned within the cavity, where advancing thepiston engages the torpedo shaped distal end with the beveled innersurface of the spikes causing them to eject through the penetrations andengage articular surfaces of a facet joint.

In another embodiment, a spinal distraction implant may include twoparallel equal length side bars and at least two struts pivotablypositioned between the side bars at each end, the struts having texturedsurfaces on each end thereof, where the struts may be pivoted to lie inplane with and parallel to the side bars and once in position in a facetjoint, may be pivoted substantially perpendicular to the side bars todistract the facet joint.

In another embodiment, a spinal joint distraction system may include adelivery device with a tubular shaft, a receiving assembly positioned ona proximal end of the tubular shaft and including a seating cavity, anda pair of forks extending from a distal end of the tubular shaft, theforks adapted to penetrate a facet joint. The system may also include achisel including a shaft with a chamfered tip, the chisel being adaptedfor slidable insertion through the delivery device. The system mayfurther include a decorticator sleevably positioned on the tubular shaftof the delivery device, the decorticator including a tubular shaftportion with a chamfered distal end, a plurality of serrated teeth atthe distal tip of the chamfered end, a beveled edge extending along theperiphery of the chamfered distal end, and a handle positioned on theproximal end of the tubular shaft portion, the handle having a boreadapted to receive a gripping tool and a threaded bore for receiving aset screw. The system may also include a driver assembly adapted forslidable insertion through the delivery device, the driver assemblyincluding an implant shaft, a handle positioned on the proximal end ofthe implant shaft, and implant holding arms extending from the distalend of the implant shaft. The system may also include an internalactuator adapted for slidable insertion through the driver assembly andfurther adapted to advance an implant distractor, the internal actuatorincluding a longitudinal shaft, a handle positioned on the proximal endof the longitudinal shaft and adapted to rotatably advance the implantdistractor, and an internal rod including an engagement feature adaptedto secure the implant distractor. The system may further include aninjector adapted for slidable insertion through the delivery device, theinjector including a longitudinal delivery shaft, a seating featurepositioned around the shaft, and a plunger adapted to pass through thelongitudinal delivery shaft causing ejection of material from the distalend of the longitudinal delivery shaft.

In another embodiment, a spinal joint distraction system may include adelivery device With a decorticator sleevably positioned thereon, achisel adapted for insertion through the delivery device, a driverassembly adapted for insertion through the delivery device and furtheradapted to hold an implant, an internal actuator adapted for insertionthrough the driver assembly and adapted to deliver and advance animplant distractor thereby distracting the implant, and an injectoradapted for insertion through the delivery device and further adapted todeliver flowable material to or around the joint.

In another embodiment, a spinal distraction implant may include an uppermember and a lower member each with a distal end, the distal end of thelower member coupled to the distal end of the upper member, and animplant distractor adapted to be advanced between the upper and lowermember and separate the upper and lower members causing the upper andlower member to pivot relative to one another about their respectivedistal ends.

In another embodiment, a spinal distraction implant may include an uppermember and a lower member each including a distal edge, a proximal edge,and two parallel lateral edges, the edges defining a generallyrectangular shape, an inner surface, an outer surface, a threaded slotpassing through the member from the inner surface to the outer surface,a truncated threaded slot passing through the member from the innersurface to the outer surface, a plurality of teeth spaced along the twoparallel lateral edges, a guide feature positioned on the proximal edge,and an interlocking scissor feature positioned on the distal edge. Theimplant may also include an implant distractor including a cylindricalbody tapering to a point at a distal end; a coil shaped thread featurehaving an abrupt proximal end and being interrupted by at least onecross-cut, and an annular stop ring; wherein the upper and lower membersmay be pivotally coupled to one another via their respectiveinterlocking scissor features, the respective guide features on theupper member and the lower member may oppose one another and may beadapted to receive and guide the distal end of the implant distractorbetween the upper and lower members, the respective threaded slots onthe upper and lower member may be adapted to receive the coil shapedthread feature, and the respective truncated threaded slots may beadapted to engage the abrupt proximal end or the at least one cross-cutof the coil-shaped thread feature.

In another embodiment, a method of distracting a facet joint of thespine may include dilating a path to a facet joint using a dilator set,inserting a chisel into the facet joint, advancing a delivery deviceover the chisel and inserting forks of the delivery device into thefacet joint, removing the chisel from the joint, inserting a driverassembly with an implant into the delivery device, seating the driverassembly in the delivery device thereby positioning the implant betweenthe forks of the delivery device and in the facet joint, inserting aninternal actuator into the driver assembly and advancing an implantdistractor into the implant thereby distracting the implant, actuating abutton on the internal actuator thereby releasing a grip on the implantdistractor and removing the internal actuator and the driver assembly,and inserting an injector and injecting a flowable material into oraround the facet joint.

In another embodiment, a method of distracting a facet joint of thespine may include inserting a chisel into a facet joint to provideinitial distraction and decorticate the surface of the joint, insertinga delivery device over the chisel to maintain the initial distraction,inserting an implant through the delivery device and into the joint, theimplant having teeth adapted to engage the surfaces of the joint,distracting the implant by advancing an implant distractor, the implantdistractor having a coil-shaped thread feature for engaging threadedslots of the implant, the implant distractor further having cross-cutthreads for engaging truncated threaded slots on the implant, wherein,advancing the implant distractor includes causing the cross-cut threadsto engage the truncated threaded slots and prevent backing out of theimplant, and releasing the implant distractor and removing the deliverydevice thereby leaving the implant and the implant distractor in placein the joint.

In another embodiment, a spinal joint distraction system may include adelivery device, a driver assembly adapted for insertion through thedelivery device and further adapted to hold an implant, and an internalactuator adapted for insertion through the driver assembly and adaptedto deliver and advance an implant distractor thereby distracting theimplant.

In another embodiment, a spinal joint distraction system may include adriver assembly adapted to hold an implant and an internal actuatoradapted for insertion through the driver assembly and adapted to deliverand advance an implant distractor thereby distracting the implant.

In another embodiment, a spinal joint distraction system may include animplant, an implant distractor adapted to engage the implant, and aninternal actuator adapted to advance the implant distractor therebydistracting the implant.

In another embodiment, a method of distracting a facet joint of thespine may include inserting a delivery device into a facet joint,inserting an implant through the delivery device and into the joint, anddistracting the implant by advancing an implant distractor.

In another embodiment, a method of distracting a facet joint of thespine may include partially engaging an implant distractor with animplant and engaging the implant distractor with an internal actuator toform an assembly, inserting the implant portion of the assembly into thefacet joint, and distracting the facet joint.

In another embodiment, a spinal distraction implant may include an uppermember and a lower member each with a distal end, the distal end of thelower member coupled to the distal end of the upper member, wherein theupper member and lower member each comprise a plurality of threadedslots adapted to engage an implant distractor.

In another embodiment, a spinal distraction implant may include an uppermember and a lower member each with a distal end, the distal end of thelower member including an interlocking scissor feature coupled to acorresponding interlocking scissor feature included on the distal end ofthe upper member.

In another embodiment, a spinal distraction implant comprising an uppermember and a lower member, each with a distal end, the distal end of thelower member coupled to the distal end of the upper member, wherein theimplant is adapted to receive an implant distractor between the upperand lower member.

In another embodiment, a spinal distraction implant may include an uppermember and a lower member, the upper member and lower member coupled atrespective distal ends, the upper and lower members being biased towarda position parallel to one another.

Further aspects of the invention will be brought out in the followingportions of the specification, wherein the detailed description is forthe purpose of fully disclosing preferred embodiments of the inventionwithout placing limitations thereon.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a delivery device and chisel positionedrelative to a facet joint of a spine, according to certain embodiments.

FIG. 1A is a perspective view of a chisel according to certainembodiments.

FIG. 2 is a perspective view of a distal end of a delivery device,according to certain embodiments.

FIG. 3 is a perspective view of a distal end of a delivery device withan advanced chisel, according to certain embodiments

FIG. 4 is a perspective view of a distal end of a delivery device withan advanced internal decorticator, according to certain embodiments.

FIG. 5 is a perspective view of a delivery device and chisel positionedrelative to a facet joint of a spine with a driving member positionedproximally to the chisel head, according to certain embodiments.

FIG. 6 is a perspective view of a delivery device with an exteriordecorticator in an advanced position, according to certain embodiments.

FIG. 6A-6C are perspective views of a delivery device and an internaldecorticator, according to certain embodiments.

FIG. 7 is a perspective view of a delivery device with an exteriordecorticator being retracted, according to certain embodiments.

FIG. 8 is a perspective view of a delivery device with a driver assemblyand implant poised for insertion into the delivery device, according tocertain embodiments.

FIG. 9 is a close-up view of a distal end of a driver assembly and adelivery device, according to certain embodiments.

FIG. 10 is close-up view of a distal end of a driver assembly, accordingto certain embodiments.

FIG. 11 is a perspective view of an implant and a distal end of a driverassembly, according to certain embodiments.

FIG. 12 is a perspective view of distal end of a driver assembly holdingan implant, according to certain embodiments.

FIG. 13 is a perspective view of a distal end of a driver assemblypositioned within a delivery device, according to certain embodiments.

FIG. 14 is a perspective view of an implant distractor, according tocertain embodiments.

FIG. 15 is a perspective view of a distal end of a driver assemblypositioned within a delivery device, according to certain embodiments.

FIG. 16 is a perspective view of an implant according to certainembodiments.

FIG. 16A is a perspective view of an implant showing a guide feature,according to certain embodiments.

FIG. 16B is a perspective view of an implant showing a guide feature,according to certain embodiments.

FIG. 17 is a side view of an implant according to certain embodiments.

FIG. 18 is a top view of an implant according to certain embodiments.

FIG. 18A is a top view of an implant showing the guide feature of FIG.16A, according to certain embodiments.

FIG. 18B is a top view of an implant showing the guide feature of FIG.16B, according to certain embodiments.

FIG. 19 is a proximal end view of an implant according to certainembodiments.

FIG. 20 is a side view of an implant according to certain embodiments.

FIG. 21 is side view of a U-member according to certain embodiments.

FIG. 22 is a perspective view of a U-member according to certainembodiments.

FIG. 23 is a perspective view of an implant according to certainembodiments.

FIG. 23A is a perspective view of an implant according to certainembodiments.

FIG. 24 is a top view of an implant according to certain embodiments.

FIG. 24A is a side view of the implant shown in FIG. 23A, according tocertain embodiments.

FIG. 25 is perspective view of a deliver device with a driver assemblyinserted and advance, according to certain embodiments.

FIG. 26 is perspective view showing the removal of the driver assemblyfrom the delivery device having left the implant behind, according tocertain embodiments.

FIG. 27 is a perspective view of an injector, according to certainembodiments.

FIG. 28 is a perspective view of a delivery device with an advancedinjector inserted and ejecting a material, according to certainembodiments.

FIG. 29 is a perspective view of an implant in a collapsed positionaccording to certain embodiments.

FIG. 30 is a perspective view of an expanded implant according tocertain embodiments.

FIG. 31 is a perspective view of an implant in a collapsed positionaccording to certain embodiments.

FIG. 32 is a perspective view of an expanded implant according tocertain embodiments.

FIG. 33 is a perspective view of an implant in a collapsed positionaccording to certain embodiments.

FIG. 34 is a perspective view of an expanded implant according tocertain embodiments.

FIG. 35 is a perspective view of an implant in a collapsed positionaccording to certain embodiments.

FIG. 36 is a perspective view of an expanded implant according tocertain embodiments.

FIGS. 37A-D include side and perspective views of an implant, accordingto certain embodiments.

FIGS. 38A-C include side and perspective views of an implant, accordingto certain embodiments.

FIGS. 39A-D include side and perspective views of an implant, accordingto certain embodiments.

FIGS. 40A-C include side views of an implant, according to certainembodiments.

FIGS. 41A-D include side and perspective views of an implant, accordingto certain embodiments.

FIGS. 42A-F include side and perspective views of an implant, accordingto certain embodiments.

FIGS. 43A-C include side and perspective views of an implant, accordingto certain embodiments.

FIGS. 44A-D include side and perspective views of an implant, accordingto certain embodiments.

FIGS. 45A-D include side and perspective views of an implant, accordingto certain embodiments.

FIGS. 46A-D include side and perspective views of an implant, accordingto certain embodiments.

FIGS. 47A-B include side views of an implant, according to certainembodiments.

FIGS. 48A-C include side and end views of an implant, according tocertain embodiments.

FIGS. 49A-C include side and perspective views of an implant, accordingto certain embodiments.

FIGS. 50A-B include side views of an implant, according to certainembodiments.

FIGS. 51A-B include side views of an implant, according to certainembodiments.

FIGS. 52A-C include side and perspective views of an implant, accordingto certain embodiments.

FIGS. 53A-C include side and perspective views of an implant, accordingto certain embodiments.

FIGS. 54A-C include side and perspective views of an implant, accordingto certain embodiments.

FIGS. 55A-C include side and perspective views of an implant, accordingto certain embodiments.

FIGS. 56A-C include side and perspective views of an implant, accordingto certain embodiments.

FIGS. 57A-C include side and perspective views of an implant, accordingto certain embodiments.

FIGS. 58A-B include side views of an implant, according to certainembodiments.

FIGS. 59A-B include side views of an implant, according to certainembodiments.

FIGS. 60A-B include side views of an implant, according to certainembodiments.

FIGS. 61A-C include side and perspective views of an implant, accordingto certain embodiments.

FIGS. 62A-C include side and perspective views of an implant, accordingto certain embodiments.

FIGS. 63A-C include side and perspective views of an implant, accordingto certain embodiments.

FIGS. 64A-C include side and perspective views of an implant, accordingto certain embodiments.

FIGS. 65A-C include side and perspective views of an implant, accordingto certain embodiments.

FIGS. 66A-C include side views of an implant, according to certainembodiments.

FIGS. 67A-C include side and perspective views of an implant, accordingto certain embodiments.

FIGS. 68A-C include side and perspective views of an implant, accordingto certain embodiments.

FIGS. 69A-C include side and perspective views of an implant, accordingto certain embodiments.

FIGS. 70A-C include side views of an implant, according to certainembodiments.

FIGS. 71A-C include side and perspective views of an implant, accordingto certain embodiments.

FIGS. 72A-C include side and perspective views of an implant, accordingto certain embodiments.

FIGS. 73A-C include side and perspective views of an implant, accordingto certain embodiments.

FIGS. 74A-C include side and perspective views of an implant, accordingto certain embodiments.

FIGS. 75A-B include side views of an implant, according to certainembodiments.

FIGS. 76A-C include side and perspective views of an implant, accordingto certain embodiments.

FIGS. 77A-C include side and perspective views of an implant, accordingto certain embodiments.

FIGS. 78A-C include side and perspective views of an implant, accordingto certain embodiments.

FIGS. 79A-C include side and perspective views of an implant, accordingto certain embodiments.

FIGS. 80A-D include side and perspective views of an implant, accordingto certain embodiments.

FIGS. 81A-C include side views of an implant, according to certainembodiments.

FIGS. 82A-F include side and perspective views of an implant, accordingto certain embodiments.

FIGS. 83A-B include side and perspective views of an implant, accordingto certain embodiments.

FIGS. 84A-B include perspective views of an implant, according tocertain embodiments.

FIG. 85 is an exploded perspective view of a kit, according to certainembodiments.

FIG. 86 is an assembled perspective view of a kit, according to certainembodiments.

FIGS. 87 and 88 are perspective views of a chisel portion of the kitshown in FIGS. 85 and 86.

FIGS. 89 and 90 are perspective views of a delivery device portion ofthe kit shown in FIGS. 85 and 86.

FIG. 91 is a perspective view of part of a driver assembly portion ofthe kit shown in FIGS. 85 and 86.

FIGS. 92 and 93 are perspective views of a part of a driver assemblyportion of the kit shown in FIGS. 85 and 86.

FIGS. 94 and 94A are views of a chisel according to certain embodiments.

FIGS. 95, 95A and 95B are views of a delivery device according tocertain embodiments.

FIG. 96 is a perspective view of a driver assembly according to certainembodiments.

FIG. 97 is a perspective view of an internal actuator according tocertain embodiments.

FIG. 98 is a perspective view of an injector according to certainembodiments.

FIGS. 99-99D are several views of a driver assembly according to certainembodiments.

FIGS. 100-101 depict relative positions of a driver assembly and adelivery device according to certain embodiments.

FIGS. 102-103 depict relative positions of an internal actuator, adriver assembly, and a delivery device according to certain embodiments.

FIG. 104 is a side view of an internal actuator according to certainembodiments.

FIG. 105 is a side view of an internal actuator according to certainembodiments.

FIGS. 106-108 are several side and cross-section view of an internalactuator according to certain embodiments.

FIG. 109 is a side view of a collet according to certain embodiments.

FIG. 110 is a side view of a longitudinal shaft of an internal actuatoraccording to certain embodiments.

FIGS. 111-113 include several views of an implant distractor accordingto certain embodiments.

FIG. 114 is a perspective view of an injector according to certainembodiments.

FIGS. 115-116 depict relative positions of an injector and a deliverydevice according to certain embodiments.

FIGS. 117-120 include several perspective views of an implant accordingto certain embodiments.

FIG. 121 includes several parts of a tool according to certainembodiments.

FIG. 122 is a perspective view of a chisel according to certainembodiments.

FIG. 123 is a perspective view of a delivery device according to certainembodiments.

FIG. 123A is a perspective view of the proximal end of a delivery deviceaccording to certain embodiments.

FIG. 124 is a perspective view of a decorticator according to certainembodiments.

FIG. 125 is a perspective view of a driver assembly according to certainembodiments.

FIG. 126 is a perspective view of an internal actuator according tocertain embodiments.

FIGS. 126A and 126B are cross-sectional views of an internal actuatoraccording to certain embodiments.

FIGS. 127 and 127A are perspective views of an internal rod with acollet according to certain embodiments.

FIG. 128 is a perspective view of an injector according to certainembodiments.

FIGS. 129-131 are several view of a dilator set according to certainembodiments.

FIGS. 132 and 132A are two views of a dilator rod according to certainembodiments.

FIGS. 133, 133A, and 133B are several views of a dilator sleeveaccording to certain embodiments.

FIGS. 134 and 134A are two views of a dilator sleeve according tocertain embodiments.

FIGS. 135, 135A, and 135B are several views of a dilator sleeveaccording to certain embodiments.

DETAILED DESCRIPTION OF THE INVENTION

The following description generally relates to devices and methods fortreating spinal stenosis. Spinal stenosis reflects a narrowing of one ormore areas of the spine often in the upper or lower back. This narrowingcan put pressure on the spinal cord or on the nerves that branch outfrom the compressed areas. Individual vertebrae of the spine arepositioned relative to each other and their separation is maintained bydiscs separating main vertebral bodies and by capsules positioned withinfacet joints. The discs and capsules are separated from the bone oftheir respective joints by cartilage. Spinal stenosis is oftenindicative of degeneration of a disc, a capsule, or the cartilage in ajoint, which leads to a compression of the joints and the narrowingmentioned.

As such, the following detailed description includes discussion of adevice for distracting a facet joint of the spine to remedy thiscondition. The device may include a tool and an implant for distractingand maintaining the distracted position of the joint. Severalembodiments of an implant are described in addition to severalembodiments of a tool. In addition, several embodiments are describedwhere the implant and the tool work together to distract the facet jointand thereafter leave the implant behind to maintain the distraction ofthe joint. In short, the device may be adapted to access a facet jointby inserting a delivery tool and an implant, forcibly separate theassociated articular surfaces with the tool, the implant, or both, andleave the implant in place to maintain the separation of the articularsurfaces. This approach may allow for maintaining the distraction of thejoint, thereby relieving symptoms associated with spinal stenosis.

The present application hereby incorporates the following U.S. PatentApplications by reference herein in their entireties: U.S. patentapplication Ser. No. 11/618,619, which was filed on Dec. 29, 2006 and isentitled Cervical Distraction Device; U.S. Provisional PatentApplication No. 61/020,082, which was filed on Jan. 9, 2008 and isentitled Methods and Apparatus for Accessing and Treating the FacetJoint; U.S. Provisional Application No. 61/059,723, which was filed onJun. 6, 2008 and is entitled Spine Distraction Device; U.S. ProvisionalApplication No. 61/097,103, which was filed on Sep. 15, 2008 and isentitled Cervical Distraction/Implant Delivery Device; U.S. ProvisionalApplication No. 61/109,776, which was filed on Oct. 30, 2008 and isentitled Facet Joint Implants; U.S. Non-provisional application Ser. No.12/317,682, which was filed on Dec. 23, 2008 and is entitled Facet JointImplants and Delivery Tools; U.S. Non-provisional application Ser. No.12/350,609, which was filed on Jan. 8, 2009 and is entitled Method andApparatus for Accessing and Treating the Facet Joint; and U.S.Provisional Application 61/169,601, which was filed on Apr. 15, 2009 andis entitled Facet Joint Implants and Delivery Tools.

Referring now to FIGS. 1-28, a first embodiment of a tool and an implantis shown. FIG. 1 shows the tool 100 in position posterior to the spine102. The tool 100 includes a delivery device 104, a decorticator 106,and a chisel 108.

The delivery device 104 may include a receiving assembly 110 at aproximal end, anchoring forks 112 at a distal end, and a generallytubular shaft 114 defining a longitudinal axis and extending between thereceiving assembly 110 and the anchoring forks 112. The tubular shaft114 may have an annular shaped cross-section with an inner radius and anouter radius, where the difference between the two radii defines athickness of the tubular shaft 114.

The receiving assembly 110 of the delivery device 104 may have agenerally conical outer surface defining a generally hollow volume orsolid mass. The conical outer surface may have a longitudinal axis thatcoincides with that of the tubular shaft 114. The conical outer surfacemay be defined by a first radius at a proximal end and a second radiusat a distal end. Where the tubular shaft 114 and the receiving assembly110 are manufactured as one piece, the second radius may match the outerradius of the tubular shaft. Alternatively, the distal end of thereceiving assembly 110 may be adapted for a press fit over the proximalend of the tubular shaft 114. The receiving assembly 110 may alsoinclude a longitudinally extending bore 116 having an inner radiusmatching that of the tubular shaft 114 or may have a conically shapedinner surface leading to the tubular shaft 114. The receiving assembly110 may also include a relatively thin annular ring 118 offset from itsdistal end by two relatively thin extension elements 120. The spacebetween the proximal end of the conical portion of the receivingassembly 110 and the distal end of the annular ring 118 may define anaccess opening 122.

In another embodiment as shown in FIGS. 6A-6C, a receiving assembly 111may not include the annular ring 118 and the extension elements 120, butmay remain generally conical and may include the longitudinallyextending bore 116. In addition, near the proximal end of the receivingassembly 111, seating recesses 119 may be included. These recesses 119may be positioned on opposing sides of the bore 116 and may recess intothe proximal end of the receiving assembly 111 and the inner surface ofthe bore 116. These recesses may function to receive positionallymatched protrusions from any one or all of the devices being insertedinto the deliver device. As such, the recesses 119, may allow fororienting the devices properly relative to the forks 112 positioned inthe facet joint. It is noted that any number of recesses may be providedand that any orientation may be used, either symmetrical ornon-symmetrical, such that one or several orientations may becontrolled. That is, an asymmetrical arrangement may allow for only oneproper insertion position as opposed to the symmetrical orientationshown, which may allow for two proper insertion positions.

As shown in more detail in FIG. 2, the delivery device 104 may includetwo anchoring forks 112 formed by coping two opposing portions of thedistal end of the tubular shaft 114. The forks 112 may have a generallyV-shaped tip 124 at their distal end and may have a generallyrectangular cross-section extending from the V-shaped tip 124 to theproximal end of the forks 112. The rectangular cross-section may have aninside face and an outside face where the inside face faces thelongitudinal axis of the delivery device 104. The rectangularcross-section may also have opposing surfaces connecting the inside faceto the outside face and completing the rectangular cross-section. At theproximal end of the forks 112, as suggested by the coping mentionedabove, the cross-section may gradually change from rectangular to ashape matching that of half of the annular shape of the tubular shaftportion. The forks 112 may also include serrations or teeth along theopposing surfaces to assist with anchoring the delivery device 104.

Referring again to FIG. 1, the chisel 108 may have a generallycylindrical cross-section forming a shaft 128. The shaft 128 may have aradius substantially equal to the inner radius of the tubular shaft 114portion of the delivery device 104 allowing for slidable insertion ofthe chisel 108 within the delivery device 104. The chisel 108 mayinclude a basic single or doubly chamfered tip 130 at a distal end ormay have a coped distal end. The chisel 108 may also include a head 132at a proximal end. The head 132 may be a generally solid material andmay have a generally flat distal face and a spherically shaped proximalface. The shaft 128 and tip 130 portion of the chisel 108, measured fromthe distal face of the head 132 to the distal end of the chamfered tip130, may have a length substantially equal to the distance from aproximal face of the annular ring 118 of the delivery device 104 to thedistal tip of the delivery device 104.

In another embodiment, the chisel 108 may include a longitudinal lumen131 as shown in FIG. 1A. While not shown, this embodiment may alsoinclude the head 132 shown in FIG. 1 and the lumen 131 may extend therethrough. The lumen 131 in the chisel 108 may be used for advancing ascope along with the chisel 108 to properly place the chisel 108 and thedelivery device 104. The lumen 131 may also be used to provide suctionor fluid flushing to the surgical site to remove or flush debris createdby inserting the serrated forks 112 of the delivery device 104 and thetip 130 of the chisel 108.

As shown in FIG. 3, the tip 130 of the chisel 108 may have a copedshaped similar to that of the forks 112 of delivery device 104. In thiscondition, the tip 130 may include a generally V-shaped distal endmatching that of the forks 112. The tip 130 may have a widthsubstantially equal to twice the inner radius of the tubular shaft 114of the delivery device 104 such that the tip 130 extends between the twoinside faces of the forks 112.

Referring again to FIG. 1, the decorticator 106 may have a tubular shaft134 portion, an abrasive distal end 136, and a handle 138 at a proximalend. The tubular shaft 134 may have an inner radius substantially equalto the outer radius of the tubular shaft 114 of the delivery device 104and may allow for sliding movement of the decorticator 106 along thelength of the delivery device 104 and rotationally around the deliverydevice 104. The abrasive distal end 136 may include serrated teeth asshown, or may include a more flat annular surface with a gritty surface.The handle 138 may have a generally cylindrical portion with randomly orpatterned raised portions or recesses adapted to assist gripping thehandle. The proximal and distal ends of the handle 138 may be generallyspherical. It is noted that the decorticator 106 may alternatively beseparate from the delivery device 104 and may be slidably insertedwithin the delivery device 104 as shown in FIG. 4. In this embodiment,the decorticator 106 may be inserted, advanced to the implantation site,and rotated similar to the decorticator 106 described above to roughenthe bone surface.

In still another embodiment, a decorticator 106 may take the form of arelatively sharp pick, as shown in FIG. 6A-6C. As shown in FIG. 6A, thedecorticator 106 may include a control handle 139 for advancing andpivoting the device. The control handle 139 may be connected to atubular shaft 135, which may be connected to a sharp flexible tip 137.As shown, the tip 137 may be relatively thin and may have a neutralposition relative to the longitudinal axis of the delivery device 104 soas to position the tip 137 within the boundary defined by the innersurface of the delivery device 104. As such, when inserted in thedelivery device 104, the tip 137 may slide readily through the deliverydevice 104. When the decorticator 106 is advanced to the distal end ofthe delivery device 104, the tip 137 may be rotated and maneuvered todecorticate the surface of the lateral mass. It is noted that the shaft135 may be relatively narrow when compared to the inner bore of thedelivery device 104 to facilitate better maneuverability of the tip ofthe decorticator as it extends out the end of the deliver device. Thedecorticator may be used as shown in FIGS. 6B and 6C to rotationallyscrape or longitudinally penetrate the lateral mass of a facet joint. Adriving member may be used to assist the decorticating process.

Referring now to FIG. 5, the tool 100 is shown with the chisel 108 fullyinserted into the delivery device 104 such that the distal face of thehead 132 of the chisel 108 is in abutting relationship with the annularring 118 of the receiving assembly 110 on the delivery device 104. Thedistal tip 130 of the chisel 108 thus extends to the distal end of thedelivery device 104. A hammer 140 is shown for use in tapping theproximal end of the chisel 108 and thus advancing the forks 112 of thedelivery device 104 and the tip 130 of the chisel 108 into the facetjoint. As the chisel 108 and the delivery device 104 are advanced intothe joint, the forks 112 of the delivery device may channel into thefact surface and displace or remove tissue. In some embodiments, thismay be removed by a suction lumen in the chisel. Once the chisel 108 anddelivery device 104 are tapped into place, the chisel 108 may be removedand the serrations on the opposing surfaces of the forks 112 may aid inanchoring the delivery device 104 in the joint and preventingdislodgement.

FIG. 6 shows the decorticator 106 in an advanced position along thelength of the delivery device 104 such that the distal end is in contactwith the bone surfaces surrounding the facet joint. The handle 138 isbeing used to rotate the decorticator 106 around the perimeter of thedelivery device 104 to roughen the associated bone surfaces.Alternatively, either of the internal decorticators shown in FIGS. 4 or6A-6C may be used.

FIG. 7 shows the decorticator 106 retracted and also shows the resultingroughened bone surfaces.

Referring now to FIG. 8, the tool 100, including the delivery device 104and retracted decorticator 106, is shown lodged in a facet joint. Alsoshown is a driver assembly 142 portion of the tool 100. The driverassembly 142 includes a distractor knob 144, an implant shaft 146,implant holding arms 148, an implant distractor 150, and an internalactuator 152 (not shown). The driver assembly 142 shown is holding animplant 154 and is poised for insertion into the delivery device 104.

Referring now to FIGS. 9-15 several views of the driver assembly 142 areshown. In FIG. 9, a portion of the delivery device 104 is shown forreceiving the driver assembly 142. The distal end of the driver assembly142 is also shown. FIG. 10 shows a close-up view of the distal end ofthe driver assembly 142 where the implant 154, the implant distractor150 and the internal actuator 152 are not shown. As shown, the implantshaft 146 of the driver assembly 142 defines a longitudinal axis thereofand has a generally annular cross-section with an inner radius and anouter radius where the difference between the two radii defines the wallthickness of the shaft 146. The outer radius of the implant shaft 146 issubstantially equal to the inner radius of the tubular shaft 114 of thedelivery device 104. The implant shaft 146 also includes a keywayfeature 156 for preventing relative rotation between the tubular shaft114 of the delivery device 104 and the implant shaft 146 of the driverassembly 142 when inserted. As shown, the keyway feature 156 may includea pair of tabs on opposing sides of the implant shaft 146 for engagingwith a corresponding longitudinal slot in the inner surface of thetubular shaft 114 of the delivery device 104. In another embodiment,this keyway feature 156 may be in the form of a longitudinal slot in theouter surface of the implant shaft 146 of the driver assembly 142, asshown in FIG. 11, which may receive an internal ridge, tab, or otherprotrusion from the inner surface of the tubular shaft 114 of thedelivery device 104.

With continued reference to FIG. 10, two arms 148 are shown extendingfrom the distal end of the implant shaft 146. The arms 148 may be formedby coping opposing surfaces of the implant shaft 146. As shown, the arms148 have a generally rectangular cross-section with an inside facefacing the longitudinal axis of the implant shaft 146 and an oppositeoutside face. The inside and outside faces of the cross-section areconnected by two opposing faces. The arms 148 may include an engagementfeature 158 at a distal end for engaging an implant 154. As shown, theengagement feature 158 may include a generally rectangular elementpositioned orthogonal to the arms 148 and flush with the outside face ofthe arms. As shown in FIG. 9, the implant 154 may slide over the distalend of the arms 148 and may include a receiving feature 160 forreceiving the engagement feature 158 of each of the arms 148.

Referring now to FIG. 11, another embodiment of the arms 148 is shown inrelation to an implant 154. In this embodiment, the arms 148 may stillbe formed by coping opposing surfaces of the implant shaft 146. In thisembodiment, the outside face of the arm 148 may be a continuation of theoutside surface of the implant shaft 146. However, the inside face ofthe arm 148 is more detailed than that of the embodiment shown in FIG.10. That is, as shown in FIG. 11, the inside surface may include alongitudinal ridge 162 extending the length of the arm 148. The arm 148may also include a bull nose engagement feature 158 extending transverseto the longitudinal axis of the implant shaft 146 along the inside faceof the arm 148. As shown in FIG. 12, where the arms 148 are engaged withand holding the implant 154, the longitudinal ridges 162 of each arm 148are positioned between upper and lower planar members of the implant 154and the bull nose engagement features 158 are positioned in the U-shapedreceiving feature slots 160 on the lateral edges of the implant 154.

The implant distractor 150 is shown in FIG. 9 and a close-up view isshown in FIG. 14. The implant distractor 150 may be a generally narrowconical element tapered to a point at a distal end. At a proximal end,the implant distractor 150 is shown to include an extruded hexagon shape164. In the present embodiment, the outer surface of the implantdistractor 150 includes a continuous coil-shaped thread feature 166. Theimplant distractor 150 is shown positioned proximal to the implant 154and engaged by the internal actuator 152. Those of skill in the art willunderstand and appreciate that the implant distractor 150 may take on avariety of shapes and sizes other than that shown in the presentembodiment. For example, the implant distractor 150 may be a triangularshaped wedge, a generally conical shape without threads, or other shapeadapted to cause separation and distraction of a facet joint.

Referring again to FIG. 9, the internal actuator 152 is visibleextending from the distal end of the implant shaft 146. The internalactuator 152 generally includes a longitudinal shaft positioned withinthe driver assembly 142. The internal actuator 152 may have a radiussubstantially equal to the inner radius of the driver assembly 142 andmay be adapted for slidable longitudinal and rotational movementrelative to the driver assembly 142. The internal actuator 152 may bemoved relative to the implant shaft 146 longitudinally, rotationally, orboth via the distractor knob 144 and may cause a corresponding motion ofthe implant distractor 150. As such, the internal actuator 152 mayadvance the implant distractor 150 into the implant 154 thus expandingthe implant 154 in the joint causing distraction of the joint. Thedistal end of the internal actuator 152 may include a hex driver typetip as most clearly shown in FIG. 15 for engaging the extruded hexagonalshaped proximal end of the implant distractor 150. Those skilled in theart will understand and appreciate that several driving engagements areknown in the art including flat screwdriver types, phillips head types,square drive, etc. and that these are within the scope of the invention.

In one embodiment, when the driver assembly 142 is inserted, it maycarry the internal actuator 152, the implant distractor 150, as well asthe implant 154 with it. However, to properly position the driverassembly 142 and the implant 154, some force may be required via amallet or other member driving member. In this embodiment, the internalactuator 152 may be slightly isolated from the driver assembly 142, soas to avoid advancing the internal actuator 152, and thus the implantdistractor 150, when forcing the driver assembly 142 into the joint.This isolation may help to avoid inadvertently advancing the internalactuator 152 and the implant distractor 150, thus avoiding inadvertentdistration prior to proper placement. The isolation of the internalactuator 152 from the driver assembly may take the form of a looselyfitting threaded engagement between the driver assembly 142 and theinternal actuator 152. Alternatively, this isolation may be in the formof a clip between the two features.

For a detailed discussion of an implant 154 according to certainembodiments, reference is now made to FIGS. 16-24.

As can be understood from FIGS. 16 and 17, the implant 154 may includeupper 168 and lower 170 members. The members 168, 170 may be generallyplanar and may also be generally rectangular. As most clearly shown inFIG. 18, each of the upper 168 and lower 170 members may include aproximal edge 172, a distal edge 174, and a pair of parallel lateraledges 176 extending longitudinally between the distal edges 174 and theproximal edges 172. The distal 174 and proximal edges 172 may begenerally square edges, while the lateral edges 176 may be defined by aradiused curve. As shown in cross-section in FIG. 19, the inner surface178 of the upper 168 and lower 170 member may be generally flat as itapproaches the lateral edge 176. Gradually, the inner surface 178departs from generally flat and follows a radiused curve until itintersects with the outer surface 180. The members 168, 170 may bejoined at their respective distal edges 174 by a U-member 182 to form aleading end. Alternatively, as shown in FIGS. 23 and 24, the leading endmay be formed via a weld (not shown) that couples the distal edges 174of the planar members 168, 170 together. In yet another embodiment, theupper 168 and lower 170 members may be formed from a single plate bentto create the implant as shown in FIGS. 23A and 24A. In any or all ofthese embodiments, the planar members 168, 170 may be biased by theleading end to be generally parallel to each other, the inner faces 178of the planar members 168, 170 facing each other in an opposed fashionand abutting or nearly abutting each other. A guide feature 184 may beincluded on each of the upper 168 and lower 170 members as well as teeth186 projecting outwardly from the outer faces 180 of the members 168,170. The receiving features 160 mentioned above with respect to FIGS. 11and 12 may also be included. Threaded slots 188 may also be included ineach planar member 168, 170 for receiving the coil-shaped thread feature166 on the implant distractor 150.

With continued reference to FIGS. 16 and 17, the guide feature 184 maytake the form of a half-conical feature and may be positioned at or nearthe proximal edge 172 of each of the upper 168 and lower 170 members.The half-conical feature may begin at the proximal edge 172 with thewidest radius of the half-conical feature and may taper to a zero orapproximately zero radius as the half-conical feature extends in thedirection of the distal edge 174. Where the upper 168 and lower 170members are in parallel position, the half conical features may opposeone another and function to receive and guide an advancing implantdistractor 150. As such, like the upper 168 and lower 170 membersdescribed above, the half-conical features may also include threadedslots 188 for receiving the coil-shaped thread feature 166 on theimplant distractor 150. In other embodiments, the half-conical featuremay not actually be a full half cone. Instead, the proximal end of thefeature may be a segment of a circle and the feature may be relativelysubtle in the form of a cone segment. In another embodiment the guidefeature 184 may include a V-shaped notch or a rectangular notch in theproximal end of the upper 168 and lower 170 members as shown in FIGS.16A and 18A and FIGS. 16B and 18B respectively. Those skilled in the artwill understand and appreciate that other shaped notches or elements maybe positioned on proximal end of the upper 168 and lower 170 members toguide the implant distractor 150, and these elements are within thescope of the present disclosure.

As shown, the upper 168 and lower 170 members may also each includeteeth 186 projecting outwardly (e.g. a direction opposite the positionof the other upper or lower member) from the outer surfaces 180 of theupper 168 and lower 170 members. As shown in FIG. 17, the teeth 186 maybe equally spaced along each lateral edge 176 and may have a linearlysloped distal face 190 and a proximal face 192 oriented orthogonally toits respective upper 168 or lower 170 member. The distal face 190 andproximal face 192 may intersect to form a point 194. The teeth 186 mayalso be bounded by opposing inside 196 and outside 198 lateral facesseparated by a thickness approximately equal to the thickness of theupper 168 and lower 170 members. As shown in FIG. 19, the outside face198 of the teeth 186 follows an extension of the radiused curve formedby the inner surface 178 of the upper 168 or lower 170 member at thelateral edge 176, this curve being referred to as a first radiusedcurve. Additionally, the inside face 196 of the teeth 186 follows asecond radiused curve offset from the first radiused curve, such thatthe teeth 186 have a generally constant thickness from the locationwhere they depart from the outer surface 180 of the upper 168 or lower170 member to the point 194. The radiused shape of the teeth 186 allowsthe implant 154 to slidably engage the inside of the delivery device 104when it is advanced toward the implantation site. Those skilled in theart will understand and appreciate that one, as opposed to both, of theupper 168 and lower 170 members may include teeth 186 to facilitatefreedom of motion of the facet joint once the implant 154 is in place.

As shown in FIGS. 16 and 17, where a U-member 182 is used to connect theupper 168 and lower 170 members, the U-member 182 may overlap the upper168 and lower 170 members. Alternatively, as shown in FIG. 20, theU-member 182 may attach to the distal ends 174 of the upper 168 andlower 170 members via a butt joint. In either case, the U-member 182 maybe fastened via welding, fusing, or other techniques known in the art.As shown in FIGS. 21 and 22, the U-member 182 may be a relatively thin,generally rectangular piece of material formed into the shape of theletter ‘U’. The rectangular piece of material may have a length definedby the amount of overlap of the upper member 168 and the lower member170 in addition to the length associated with hairpin or U portion ofthe member 182. The width of the rectangular plate may be substantiallyequal to the distance between the teeth 186 of the upper 168 and lower170 members. The U-member 182 may be adapted to provide the parallelbiased position mentioned and yet allow distraction of the upper 168 andlower 170 member when a separation force is applied, the proximal edge172 of the upper 168 and lower 170 member distracting more than thedistal edge 174.

As shown in FIGS. 23 and 24, where the distal edges 174 of the upper 168and lower 170 member are joined via welding, the distal edges 174 mayinclude a notch to facilitate more weld length and to cause flexure tooccur in the upper 168 and lower 170 members rather than in the welditself. Also shown in FIGS. 23 and 24 are the U-shaped receiving featureslots 160 for receiving the bull nosed engagement features 158 of thearms 148 of the driver assembly 142. As shown most clearly in FIG. 24,the U-shaped receiving feature slots 160 are positioned between theequally spaced teeth 186 and extend into the lateral edges 176 of theupper 168 and lower 170 member just beyond the inside edge of where theteeth 186 begin extending from the outer surfaces 180.

The receiving feature 160 may take several forms including a rectangularnotch in the lateral edge 176 of the upper 168 and lower 170 member or aU-shaped notch. The receiving feature 160 may be adapted to receive anengagement feature 158 positioned on the arm 148 of the driver assembly142. The receiving feature 160 may be any shaped recess and may beadapted to be engaged by the engagement feature 158 so as to prevent orlimit relative longitudinal motion between the arms 148 and the implant154, when the implant 154 is in the neutral position. However, when inan expanded or distracted position, the receiving features 160 may besuch that they are lifted free of the engagement feature 158 of the arms148, thus allowing relative longitudinal motion between the driverassembly 142 and the implant 154.

The driver assembly 142 and implant 154 described with respect to FIGS.8-24, may be used to distract a facet joint. With the delivery device104 positioned as shown and described with respect to FIG. 7, theimplant 154 may be positioned to be held by the arms 148 of the driverassembly 142. The driver assembly 142 and implant 154 may then beinserted into the delivery device 104 and slidably advanced such thatthe implant 154 is positioned between the forks 112 of the deliverydevice 104 and within the facet joint. The advanced position of thedriver assembly 142 and implant 154 within the delivery device 104 maybe most clearly seen in FIG. 13. The proximal end of the driver assembly142 may be tapped on to fully advance the driver assembly 142 andproperly position the implant 154. The implant shaft 146 of the driverassembly 142 may be prevented from rotating by the keyway feature 156securing it against relative rotation with respect to the deliverydevice 104. As such, once positioned, the distractor knob 144 of thedriver assembly 142 may be turned, as shown in FIG. 25, therebyadvancing the internal actuator 152 and further advancing the implantdistractor 150. In the embodiment described, the coil-shaped threadfeature 166 on the implant distractor 150 may engage the threaded slots188 of the half-conical features 184 of the upper 168 and lower 170members of the implant 154. As such, the implant distractor 150 may beguided and remain in position to further engage the threaded slots 188on the upper 168 and lower 170 members. As the implant distractor 150continues to advance, those of skill in the art will understand andappreciate that its tapered shape advancing between the upper 168 andlower 170 members will force the upper 168 and lower 170 members of theimplant 154 apart causing them to pivot about a point defined by theattachment to each other at their distal ends 174. As the implant 154continues to be distracted, the upper 168 and lower 170 members of theimplant 154 are laterally separated such that they clear the engagementfeatures 158 on the arms 148 of the driver assembly 142. As shown inFIG. 26, when the implant distractor 150 has been fully advanced and theimplant 154 is in place, the driver assembly 142 may be slidably removedfrom the delivery device 104 leaving behind the implant distractor 150and the implant 154.

FIG. 27 shows yet another device, the device being adapted for placingbone paste over the implant 154 in the joint. An injector 202 is shownand includes a syringe type cannula 204 with a closed distal end 206 andtwo exit doors 208 positioned on opposite sides of the distal end 206 ofthe cannula 204. The cannula 204 includes a plunger 210 with a seal andfurther includes a stopping disc 212 at its proximal end, the plunger210 penetrating the stopping disc 212 and having a handle 214. Thecannula 204 may have an outer radius substantially equal to that of theinner radius of the delivery device 104 to allow for slidable engagementof the two devices. The disc 212 at the proximal end is generally flatand is adapted to engage the receiving assembly 110 of the deliverydevice 104 and provide a stop point for the injector 202 when insertedinto the delivery device 104. As shown, the cannula 204 may contain abone paste material in a liquid form.

As shown in FIG. 28, the injector 202 may be inserted into the deliverydevice 104 and slidably advanced such that the distal end 206 is nearthe implantation site and the disc 212 abuts the annular ring 118 of thereceiving assembly 110 of the delivery device 104. The injector 202 maybe rotatably positioned such that the doors 208 are positioned to openperpendicular to a line connecting the distal ends of the forks 112. Thedisc 212 may include tabs 216 for such positioning relative to theannular ring 118 on the receiving assembly 110. Once in position, theplunger 210 may be actuated to compress the bone paste material creatingan internal pressure which forces the exit doors 208 open allowing thebone paste to escape and flow over the implantation site.

The above description has included some references to use to allow for abetter understanding of the structure. Below is a more detaileddiscussion of that use including the devices and techniques fordistracting and retaining a facet joint in a distracted and forwardlytranslated condition. The implantation procedure may be performed underconscious sedation in order to obtain intra-operative patient symptomfeedback.

Initially an incision may be made in the patients back. Tools known inthe art may be used to create this incision and to open an access paththrough the tissues of the back to access the spine. Once an access pathis created, the chisel 108 described above may be inserted into thedelivery device 104 and the two of them may be inserted through theincision and the distal tip 130 may be positioned adjacent the targetfacet joint. It is noted that visualization may be provided by firstinserting a scope down the delivery device 104 rather than the chisel108. Additionally, an incision in the facet joint capsule may be madeprior to beginning the procedure, and thus prior to insertion of thechisel 108. Once the distal tip of the delivery device 130 is properlypositioned adjacent the facet joint and any other preparation steps arecompleted, the chisel 108 may be inserted. Once the chisel 108 anddelivery device 104 are properly positioned, the head 132 of the chisel108 may be tapped with a driving device 140 such as a hammer or otherinstrument to advance the distal tip 130 of the chisel 108 and the forks112 of the delivery device 104 into the facet joint. Once the deliverydevice 104 is properly positioned, the chisel 108 may be removed. Atthis point, the implant 154 may be placed in the driver assembly 142 andthe implant 154 and driver assembly 142 may be slidably advanced throughthe delivery device 104. The forks 112 of the delivery device 104 may beholding the facet joint slightly distracted. As such, the implant 154,in its flat and parallel position, may slide relatively easily into thefacet joint. To the extent that it does not, the proximal end of thedriver assembly 142 may be tapped to properly advance and position theimplant 154. Once properly positioned, the distractor knob 144 on thedriver assembly may be rotated or otherwise actuated to activate theinternal actuator 152. The internal actuator 152 advances the implantdistractor 150 into the implant 154 and thus distracts the implant 154.It is noted here that the distraction of the implant 154 may cause theupper 168 and lower 170 member of the implant 154 to clear theengagement features 158 of the holder arms 148 thus allowing the driverassembly 142 to be freely removed from the delivery device 104 leavingthe implant 154 and the implant distractor 150 behind. The injector 202may then be advanced through the delivery device 104 and positioned toallow the doors 208 to open in a direction approximately perpendicularto the forks 112 of the delivery device 104. The handle 214 may bedepressed thus advancing the plunger 210 and ejecting the bone paste orother anchoring material. The injector 202 may then be removed. Thedelivery device 104 may also be removed and the incision closed.

Those skilled in the art will understand and appreciate that severalmodifications or variations from the above the identified embodimentsmay be made while still falling within the scope and spirit of thepresent disclosure. For example, several alternative actuationmechanisms at the proximal end of the tool for actuating the distractingelements of the tool may be available. Additionally, several alternativeimplants may be available. For example, as shown in FIGS. 29 and 30, animplant 218 similar to that previously described is shown and includes abody 220 and a screw 222. The body 220 includes an upper 224 and lower226 face joined together at a leading end 228 and separated from eachother at a trailing end 230.

As shown in FIG. 29, when the screw 222 is not received in the body 220,the upper 224 and lower 226 faces may reside against each other suchthat the body 220 is generally flat. As shown in FIG. 30, when the screw222 is received in the body 220, the upper 224 and lower 226 faces maybe separated from each other, the degree of separation increasing as thescrew 222 is increasingly received in the body 220. As the upper 224 andlower 226 faces are separated from each other, the body 220 takes onmore of a wedge shape, with the leading end 228 being the narrow end ofthe wedge and the trailing end 230 being the wide end. The faces mayinclude teeth 232 and the trailing end 230 of the upper face 224 may beformed to project towards the leading end, both of these featuresassisting in the implant 218 anchoring to the bone facet surfaces. Holes234 may exist in the faces 224, 226 such that when the screw 222 isreceived in the body 220, the thread edges of the screw 222 may projectthrough the holes 234 to bite into the facet surfaces. The wedge shapeof the implant 218 may facilitate anchoring the implant 218 within thefacet joint and may also facilitate distraction, translation, orsubluxation of the facet surfaces relative to each other.

As can be understood from FIG. 29, the collapsed and flattened body 220may be placed between the opposing surfaces of the facet joint. Theposterior or trailing end 230 of the body 220 is configured to becapable of receiving a screw, bolt, or some other inserted component222. As indicated in FIG. 30, upon insertion of the screw, bolt, etc.222, the body 220 begins to expand. This expansion and separation isenabled by a hinge 236 at the anterior or leading end 228 of the body220. As the body 220 expands, sharp directional teeth, cleats, or keels232 on the opposing (superior & inferior) surfaces or faces 224, 226 ofthe body 220 may become anchored in the cortical bone of the opposingfacet surfaces. These teeth, cleats, or keels 232 may engage the facetsurfaces and provide acute fixation of the body 220 within the facetjoint. The teeth, cleats, or keels 232 may be included on only onesurface 224, 226 as opposed to both surfaces 224, 226 so as to allow fora movement of the joint after placement of the implant 218.

The distraction and separation of the facet joint via the expandedimplant (see FIG. 30) may increase foraminal area and reduce thesymptoms associated with nerve root compression.

Another implant embodiment is depicted in FIGS. 31 and 32, wherein ascrew 238 also acts to spread apart the faces 240, 242 of the body 244of the implant 236. In this embodiment, the implant 236 may have anupper 240 and a lower 242 member positioned adjacent to each other. Theupper 240 and lower 242 member may be substantially rectangular with adistal edge a proximal edge and parallel lateral edges. The distal edgemay be slightly radiused. The upper 240 and lower 242 members may beconnected along their distal edge by a connection member 246 in the formof a triangularly bent plate or other connection. The connection membermay include a penetration 248 adapted to receive an implant distractor238. As with the previous embodiments, the implant 236 may include teeth250 on the outer surface of the upper member 240 or the lower member 242or both as shown. In one embodiment, the implant 236 may be formed froma single plate and folded to create the shape shown. In use, the implant236 may be positioned in a facet joint and the implant distractor 238may be advanced thereby separating the upper 240 and lower 242 memberand distracting the joint. Similar to that discussed above with respectto FIGS. 29 and 30, such an embodiment as depicted in FIGS. 31 and 32may have holes (not shown in FIGS. 31 and 32) in the body surfaces 240,242 so as to allow the threads of the implant distractor 238 to extendthrough the surfaces of the body 244 to bite into the facet surfaces.

FIGS. 33 and 34 depict isometric views of another implant 248 withV-shaped members 250 residing on a threaded bolt 252 between an anteriorthreaded block 254 and a posterior non-threaded block 256. The V-shapedmembers 250 may slidably engage the bolt 252. As shown in FIG. 33, theV-shaped members 250 are in a non-expanded state and are spaced apartfrom each other along the length of the bolt 252. The implant 248 may beinserted into the facet joint in the non-expanded state depicted in FIG.33. As can be understood from FIG. 34, the bolt 252 may be rotated tocause the anterior threaded block 254 to travel along the bolt 252towards the posterior non-threaded block 256. It is noted that in use,the rotation of the blocks 254, 256 may be prevented by their positionwithin a facet joint, thus causing the anterior threaded block 245 totravel rather than rotate when the bolt 252 is rotated. The posteriornon-threaded block 256 may be in abutting position against the head 258of the bolt 252 thereby preventing it from moving away from the anteriorthread block 254. Thus, as the anterior threaded block 254 advancestoward the posterior non-threaded block 256, the V-shaped members 250are squeezed together. As the V-shaped members 250 are increasinglysqueezed together between the blocks 254, 256, the V-shaped members 250are increasingly expanded outward, thereby biting into the facet jointsurfaces to anchor the implant 248 in the facet joint and distract,translate and/or subluxate the facet surfaces relative to each other.

FIGS. 35-36 and 37A-D, depict isometric views of another implant 260with planar plates or leaves 262 residing on a threaded bolt 264 andparallel shafts 266 between an anterior threaded block 268 and aposterior non-threaded block 270. As shown in FIG. 35, the planar plates262 are in a skewed non-expanded state and are spaced apart from eachother along the length of the bolt 264 such that may lie generally flator, more specifically, at approximately 45 degrees on the bolt 264 andshafts 266. The plates 262 may include a slotted hole for receiving thebolt 264, which allows for the position described. The implant 260 maybe inserted into the facet joint in the non-expanded state depicted inFIG. 35. As can be understood, the bolt 264 may then be rotated to causethe anterior threaded block 268 to travel along the bolt 264 towards theposterior non-threaded block 270, thereby causing the planar plates 262to squeeze together. As the planar plates 262 are increasingly squeezedtogether between the blocks 268, 270, the planar plates 262 areincreasingly expanded outward or, more specifically, are caused to begenerally perpendicular to the bolt 264 and shafts 266. As a result, theplanar plates 262 bite into the facet joint surfaces to anchor theimplant 260 in the facet joint and distract, translate and/or subluxatethe facet surfaces relative to each other.

FIGS. 37A-D show an embodiment, which combines features of theembodiment shown in FIGS. 33 and 34 with features of the embodimentshown in FIGS. 35 and 36.

FIGS. 38A-C shows another embodiment of an implant 272. The implant 272may include two stacked structures 274 that interface along a plane 276.Each structure 274 may include opposing ratchet teeth 278 along theplane. The position and orientation of the ratchet teeth 278 may be suchthat relative translation between the two structures 274 is allowed whena force is applied to each structure 274 in opposing directions. Thatis, once the implant 272 is properly positioned within the facet, adevice may be use to apply a force to the superior structure 274 whichcauses forward translation of that structure 274 relative to theinferior structure 274. The ratchet teeth 278 on the superior structure274 may slide up the slope of the teeth 278 on the inferior structure274 until opposing apexes of teeth 278 pass by each other causing thetwo structures 274 to nest in a new relative position, the displacementbeing equal to the length of the teeth 278. Each structure 274, or onlyone of the structures 274, may increase in thickness along its length,such that continual relative ratcheted displacement creates a greateroverall thickness. The increasing thickness of the implant structures274 may cause distraction and forward translation in the facet joint.The opposing facet surfaces may be separated and the superior vertebramay be pushed anterior relative to the inferior vertebra. In addition,anchoring teeth 280 may be provided on the outer surface of bothstructures 274 of the implant 272 to provide acute fixation to thearticular surfaces. The implant 272 may be configured in a number ofdifferent shapes including, but not limited to, a wedge, a double wedge,a rectangular box, and “v”shaped.

FIGS. 39A-D show another embodiment of an implant 282. In thisembodiment, a screw like implant 282 may be inserted between the facet.The insertion of this screw may serve to distract the joint surfacesresulting in a decompression of the nerve root. Additionally, thethreads 284 of the screw may include V-shaped notches 286 in the threads284 spaced throughout the length of the screw creating serrated teeth.As the screw implant 282 is threaded progressively further anterior, theserrated teeth may cut/bore into the cortical bone of the opposing facetsurfaces. The defect in the bone these serrations produce may preventthe implant 282 from backing out posteriorly or migrating medial/lateralbecause the threads 284 are configured with the serrated teeth to allowthe implant 282 to catch or “bite” in the bone if any posterior withdrawor backing out occurs. Additionally or alternatively, as shown in FIGS.40A-C, the screw threads 284 may include a leaf spring 288 to maintainfriction of the threads 284 against the newly cut threads in the bonethereby preventing the screw from backing out.

FIGS. 41A-D show another embodiment similar to the one shown in FIGS.39A-D. That is, in this embodiment, the implant 290 may take the form ofa screw, but the threads 292 of the screw may have a T-shaped profile asshown in FIG. 41D. In addition, the flat surface of the T-shaped profilemay define a diameter at any given point along the length of the screw.In one embodiment, the diameter may increase over the length of thescrew and not be limited to just the tip like a traditional screw. Assuch, when the implant 290 is placed, the more it is advanced into thefacet joint, the more separation it creates.

FIGS. 42A-F show another embodiment of an implant 294. In thisembodiment, the implant 294 may again take the form of screw. The screwmay have a washer or extra broad head 296 with sharp protrusions 298 onthe distal surface of the head 296 that engage the superior and inferiorlateral mass surfaces as the screw is inserted into the facet joint. Theengagement of the sharp protrusions 298 may occur as a result of boththe longitudinal translation of the screw together with the rotationalmotion causing the sharp protrusions 298 to cut into the lateral masssurface as the screw is advanced and rotated. As the washer 296 rotates,the sharp protrusions 298 roughen the lateral masses and create afracture environment. This fracture environment causes osteoblasticactivity that will lead to bone production and assist in fusion of thejoint at the lateral mass. Moreover, the moat created by the rotatingand cutting protrusions 298 may begin to lock the facet surfacestogether.

In the present embodiment, the protrusions 298 may be tab like and cutrelatively deeply into the lateral mass. In addition as shown in FIGS.42D-F, the tabs may position themselves as shown where the superior tabis flared to engage the lateral mass and the inferior tab is wedged intothe joint. In this configuration, the tabs may act to further distractthe joint beyond that provided by the diameter of the screw portion ofthe impant. In other embodiments, as shown in FIGS. 43A-C, the sharpprotrusions 300 may be sharp prongs or spurs adapted to roughen thesurface.

FIGS. 44A-D show another embodiment of an implant 302. In thisembodiment, a facet distraction implant 302 has a floating collar 304for use with a screw type implant. As shown, the collar 304 may bepositioned to pivot about the head 306 of the screw due to the sphericalshaped head 306 on the screw in a ball and socket fashion. The floatingcollar 304 allows the screw implant to accommodate irregular, non-planarsurfaces of the lateral mass and may aid in the prevention of reversethreading of the implant 302 once the screw has been advanced to theproper position within the facet. As shown, the screw may be implantedto provide distraction and forward translation of the joint. Thefloating collar 304 may include teeth or spikes 308 thatroughen/decorticate the cortical bone of the superior and inferiorlateral masses resulting in the creation of a fracture environment. Thismay improve the chance of posterior lateral mass facet fusion.

FIGS. 45A-D show yet another embodiment of a decorticating screw typeimplant 310.

FIGS. 46A-D show another embodiment of an implant 312. In thisembodiment, a structural implant 312 is inserted between the opposingsurfaces of a facet joint. This implant 312 may be in the form of ascrew as described above or may be a different implant requiring atorque or other force to be applied to anchor the implant 312 in thefacet joint. As shown, when the implant 312 is inserted increasinglymore anterior within the facet, a torque limiting mechanism 314 withinthe device may measure the force or torque applied to the system. Once apredetermined value of torque or force is achieved, the distal end ofthe system may detach causing the implant 312 to become a permanentdistraction implant.

In the case of a screw implant, the torque limiting mechanism 314 may bea necked down portion of the device creating a calibrated weakenedportion intended to fail when a specified torque is exceeded.

In this embodiment, the implant 312 may also include a number of unitmigration features to prevent backout. These features may includedirectional teeth, roughened surfaces, keels, spikes, or other featuresknown in the art. As with other implants, the geometry of the implantmay cause distraction of the joint and lead to a more pronounced forwardtranslation of the joint as the opposing facet surfaces separate.

FIGS. 47A-B show another embodiment of an implant 316. In thisembodiment, again a screw shaped implant 316 may be inserted into thefacet to distract the facet surfaces and increase foraminal heightresulting in a decompression of a symptomatic nerve root. In thisembodiment, however, the implant may include two main components. First,the implant 316 may include a relatively stiff but maleable cone-shapedscrew structure 318 with aggressive threads for biting into the opposingsurfaces of the facet joint. These threads may have a number ofvariations for preventing movement of the implant after it is implanted.Second, the implant may include an inner core support member 320. Thecore support member 320 may be in place when the implant 316 is placedto assist in maintaining the shape of the screw structure 318. Afterplacement, the core support member 320 may be removed. The maleabilityof the screw structure 318 may allow it to collapse slightly once theimplant 316 is properly positioned and inserted. The collapsing of thescrew structure 318 would change the alignment of the threads andprevent reverse threading that could lead to posterior migration.

Yet another embodiment is show in FIGS. 48A-C. In this embodiment, asuperior 324 and an inferior 326 screw may be used to create an implant322. The two screws 324, 326 may have communicative threaded serrationsthat work in opposition to one another. As such, when the inferior screw326 is rotated, the threads may interact with the superior screw 324causing it to rotate in the opposite direction. Moreover, the threads onthe inferior screw 326 and superior screw 324 are such that oppositedirection rotation draws both screws 324, 326 in to the facet joint. Asthe screws 324, 326 enter the joint, the facet surfaces are distractedapart from one another and the threads of the screw bite into the facetsurfaces. The opposing rotation of the two screws 324, 326 may alsoassist in preventing back out of the implant or reversethreading/unscrewing. It is noted that several configurations may beused to create the opposite rotation of the screws. In one embodiment, ahousing may be placed over each screw allowing the screws to freelyrotate relative to the housing, but securing the screws adjacent to oneanother. In this embodiment, the opposite rotation may occur due to thethreads engaging with one another as described above or the screw headsmay have gear teeth for engaging one another and causing oppositerotation. In another embodiment, the screws may have gears on thempositioned within the housing to engage one another and cause oppositedirection rotation.

FIGS. 49A-C show yet another embodiment of an implant 328. In thisembodiment, a translating system including a vertical plate 330 and abumper 332 may be included. The superior aspect 334 of the bumper 332may have a rounded concave surface for opposing the lateral mass of asuperior vertebra. The translating system may be secured by anchoring ascrew 336 to the lateral mass of an inferior vertebrae. The screw 336may act as the foundation for a bumper system intended to push asuperior vertebra forward (anterior) creating translation of thesuperior vertebra relative the the inferior vertebra. This forwardtranslation may create an increase in foraminal area and results in adecompression of the nerve root. The implant 328 may be configured tomaintain permanent forward translation in order to prevent foraminalnarrowing and nerve root compression. In addition, the implant 328 mayprovide rigid resistance when the superior vertebra exerts posteriortranslation vectors because it is anchored by the inferior lateral massscrew. The prevention of this posterior translation may keep the segmentin a state of forward translation and preserve the associated increasein foraminal area.

FIGS. 50A-B show another embodiment of an implant 338. In thisembodiment, a wedge shaped or triangular implant 338 may be insertedbetween the face surfaces. The angled/pointed portion 340 with two acuteline segments may allow the implant 338 to enter into the flat facetjoint when sufficient force is applied. As the implant 338 is insertedprogressivley more anterior, the distraction of the opposing facetsurfaces may increase. This separation results in an increase offoraminal height and decompresses the symptomatic nerve root.

The surfaces of this implant 338 may include teeth, spikes, cleats,surface roughening, and/or keels 342 to help prevent migration orbackout. In another configuration of this embodiment, as shown in FIGS.51A-B, the wedge shaped or triangular implant 338 may be anchored inposition by one or two (one shown in FIG.) lateral mass screws/nails 344that would connect the superior & inferior aspects of the implant 338 tothe corresponding superior & inferior lateral masses of the affectedsegment.

FIGS. 52A-C show another embodiment of an implant 346. In thisembodiment, a distraction/translation system may include an anteriorhook 348 and a posterior hook 350 joined by a threaded bolt 352. Theanterior hook 348 may be placed over the anterior aspect of the inferiorfacet and the posterior hook 350 may be positioned posterior to thesuperior facet. The anterior hook 348 may have a C-shaped profile with alip for engaging the anterior aspect of the inferior facet. Theposterior hook 350 may have a S-shaped profile with a lip for engagingthe posterior aspect of the superior facet. The threaded bolt 352 may bepositioned through the facet joint and may threadably engage a posteriorleg 354 of the anterior hook 348 and an anterior leg 356 of theposterior hook 350 as shown. As the bolt 352 is tightened and the hooks348, 350 are drawn together, they create anterior translation of thesuperior vertebra relative to the inferior vertebra. This translationmay result in increased foraminal area and nerve root decompression. Thetranslation is maintained through the permanent placement of the hooksand bolt.

FIGS. 53A-C show another embodiment of an implant 358. In thisembodiment, an insert 360 may be placed in the facet joint between twoopposing facet surfaces. The geometry of the implant 358 could take anumber of shapes including, but not limited to, rectangular, concical,triangular, or trapezoidal shape. Once the implant 358 is properlypositioned, it may then be rotated some degree of rotation. Thisrotation may result in an increased height of the implant and causefacet surface separation and thus increased foraminal area anddecompression of the symptomatic nerve root. In another configuration asshown in FIG. 53C, the rotated implant 358 may have outer tabs 362 thatare capable of receiving a bone screw, nail, or pin that can be anchoredin the superior and inferior lateral masses. These tabs 362 and anchorsmay assist in the prevention of implant migration leading to a reductionin the foraminal area.

FIGS. 54A-C show another embodiment of an implant 364. In thisembodiment, an implant 364 may take the form of a collapsible diamondshape 366 with an adjustment bolt 368 abutting a first corner 371 andthreaded through an opposing corner 370 of the shape. The other corners372 may include pads 374 for positioning against opposing articularfaces of a facet joint. The implant 364 may be placed into the facetjoint in a collapsed position and the adjustment bolt 368 may then beactuated to draw the opposing corners 371, 372 of the shape togetherthereby expanding the shape and pressing the pads 374 against thearticular faces. As the shape expands, additional facet distraction isachieved resulting in an increased foraminal opening. This implant 364may be provided in a number of geometries or materials to providedirectional distraction where, for example, more distraction occurs nearthe posterior edge of the facet relative to the anterior edge of thefacet. Additionally, the surface of the pad 374 may include teeth orkeels to enable bone purchase in the facet.

FIGS. 55A-C show another embodiment of an implant 376. In thisembodiment, the implant 376 may take the form of an expandable hingedstructure with an upper member 378 and a lower member 379 connected attheir distal ends 380 by a hinge 382. The implant 376 may be placedbetween the facet surfaces in a collapsed state. The posterior aspect ofthe implant 376 may include a receiving slot that is able to receive ascrew, bolt, or other activation system. Engaging this slot with anactivator would cause the implant 376 to expand on its hinge 382creating distraction and translation of the joint. For example, theactivator may be a wedge, a turnable flat tool, a tapered screw, or anyother device that may be inserted into the receiving slot to forciblyexpand the upper 378 and lower 379 members. As shown, the hinge 382 mayalso include a brace member 384 for maintaining the posterior halves ofthe hinge in a separated position. The brace member 384 may be springloaded or otherwise engaged with the hinge halves 378, 379 such thatwhen expanded the brace 384 moves into position to support the openposition of the hinge 382. In some embodiments, the upper 378 and lower379 member of the implant 376 may have teeth, cleats, or keels 386 toengage the cortical bone of the opposing facet surfaces. Thesemechanisms would provide fixation of the implant 376 to the joint.

FIGS. 56A-C include another embodiment of an implant 388. In thisembodiment, a collapsed and flattened structure 390 may be placedbetween the opposing surfaces of the facet joint. The posterior aspect392 of the structure 390 may be configured to be capable of receiving ascrew, bolt, or some other inserted component 394. Upon insertion of thescrew, bolt, etc. 394, the structure may begin to expand. This expansionand separation may be enabled by a hinge 396 at the anterior aspects ofthe structure 390. As the structure 390 expands, sharp directionalteeth, cleats, or keels 398 on the opposing (superior & inferior)surfaces of the structure may become anchored in the cortical bone ofthe opposing facet surfaces. These teeth, cleats, or keels 398 mayengage the face surfaces and provide acute fixation of the structurewithin the facet joint. Together with the these teeth, cleats, or keels398, or as an alternative to them, as shown, the proximal end of theimplant 388 may also include flanges 400 that overlap the lateral massof the facet joint. These flanges 400 may include holes 402 foranchoring the implant 388 to the superior and inferior facet masses, orto only one of the masses. In a related embodiment, the superior andinferior surfaces may have open ports 404 that enable the screw threadsto exit the structure and gain purchase in the opposing facet surfaces.The distraction and separation of the joint may increase foraminal areaand reduce the symptoms associated with nerve root compression.

FIGS. 57A-C show yet another embodiment of an implant 406. In thisembodiment, the implant 406 may resemble a screw and wall anchor. Thewall anchor portion 408 may be generally cylindrically shaped andinclude two half sections 410 separated by a slot or it may include amultitude of longitudinally extending sections 410. These sections 410may be connected together at the tip 412 as shown or they may beconnected together at the proximal end 414 of the implant 406 and at thetip 412 and may include several connections along the length of theimplant 406. The implant 406 may have a sharp, triangular or conical tip412 that allows for access into the flattened facet joint. Once theimplant 406 is inserted into the facet surface, a screw, bolt, or otherinsertion component 416 may be inserted into the implant 406. As thiscomponent 416 is advanced the sections 410 may expand creatingadditional separation of the joint and allowing for measured distractionof the space. The sections 410 of the wall anchor portion 408 mayinclude sharp directional teeth, cleats, or keels 418 that engage thecortical bone of the opposing facet surfaces.

FIGS. 58A-B show yet another embodiment of an implant 420. In thisembodiment, a tool 422 may be used to apply a force to the superiorvertebra of a motion segment. This forward translation would result inan increase in foraminal area and reduced nerve root decompression.Following the forward translation of the motion segment, an angled screw424 would be placed through the superior facet surface, facet capsule,and inferior facet surface. This screw 424 would provide temporaryimmobilization of the joint which leads to fusion.

FIGS. 59A-B show yet another embodiment of an implant 426. In thisembodiment, a collapsed, triangular shaped implant is inserted into thefacet. The implant 426 may include a central shaft 428 and two or morespringing leaves 430. The leaves 430 may be connected to the distal endof the shaft 428 and may extend proximally along the shaft 428. Theleaves 430 may be connected at the distal end so as to be biased in adirection to form an arrow shape. The leaves 430 may be held in thecompressed state by an insertion & delivery tool 432. The deliverytool's compression of the implant 426 prevents the superior and inferiorsurfaces of the implant 426 from springing open to a distractedposition. Once the compressed implant 426 is positioned correctly, thedelivery tool 432 may be removed. Removing the tools causes the leaves430 to open/expand causing distraction and separation of the facet jointthus resulting in increased foraminal area and reduced nerve rootcompression.

FIGS. 60A-B show yet another embodiment of an implant 434. This concepthas at least three embodiments. The first embodiment consists of adirection facet joint screw 436 that is advanced through an inferiorfacet until it makes contact with the opposing superior facet. Once thescrew 436 makes contact with superior facet surface, the energy appliedto advance the screw 436 results in distraction and separation of thejoint due to bearing of the screw tip 438 on the underside of thesuperior articular surface. In one variation of this embodiment, thehole for the screw in the inferior facet may be pre-drilled. When thescrew is installed and encounters the superior facet, the screw may biteinto the superior facet as it forces the fact upward and distracts thejoint. Alternatively, in this embodiment, the screw may have a blunt tip438 to distract the joint without biting into the superior facet.

In the second embodiment, as shown, a directional facet screw 436 may beadvanced through the inferior facet surface until it engages with afacet spacer/plate 440 that is inserted in between the facet surfaceswithin the facet capsule. As the screw 436 makes contact with the facetspacer/plate 440, the flat surface of the spacer/plate 440 may push upagainst the opposing superior facet surface causes distraction andforward translation. This separation of the facet surfaces results inincreased foraminal area and reduced nerve root compression.

In a third embodiment, the spacer/plate 440 may have a shape to allowthe screw 436 to pass through a first end and the other end to be placedin the facet joint. In this embodiment, the C-shaped spacer 440 may bepositioned in the joint, thereby slightly distracting the joint. Thescrew may then penetrate a first end of the spacer 440 thereby anchoringthe spacer 440 in the joint. The screw may then be advanced through theinferior facet surface until it engages with the spacer/plate 440. Asthe screw 436 makes contact with the facet spacer/plate 440, the flatsurface of the spacer/plate 440 may push up against the opposingsuperior facet surface causes distraction and forward translation. Insome embodiments, the screw may penetrate the spacer and aid in fixingthe joint.

FIGS. 61A-C show yet another embodiment of an implant 442. In thisembodiment, bracket type structures 444 may be attached to the superiorand inferior lateral masses. The bracket type structures 444 may enablethe attachment of a single bolt 446. The bolt 446 may be configured tocreate a distraction energy. That is, it may be connected to theinferior bracket 444 to allow rotation but not relative translation. Incontrast, the bolt may threadably engage the superior bracket 444. Assuch, when the bolt 446 is “unscrewed” it may function to push theinferior and superior brackets 444 apart. This distraction may result inincreased foraminal area and reduction in nerve root compression.

FIGS. 62A-C show yet another embodiment of an implant 448. In thisembodiment, bracket type structures 450 may each have a leg 452 forpositioning within a facet joint and another leg 454 for receiving abolt 456. As with the bracket above, the bolt 456 may be configured tocreate distraction energy. That is, it may be connected to one of thesuperior or inferior bracket 450 so as to allow rotation but notrelative translation. The other bracket 450 may threadably engage thebolt 456. As such, when the bolt 456 is “unscrewed” it may function topush the brackets apart resulting in and increased foraminal area.

FIGS. 63A-C show yet another embodiment of an implant 458. In thisembodiment, a triangular shaped implant 458 including a bent plate and afiller wedge may be inserted in the facet joint. As the triangularimplant 458 is inserted progressively more anterior, the joint may bedistracted to an optimal level. Once the desired distraction isachieved, an anchoring screw 460 may be inserted through the implant 458and into the inferior lateral mass. The superior aspect of the implant458 may include a metal flap 462 with teeth, spikes, or cleats 464. Thismaleable flap 462 may be contoured to the superior lateral mass andanchored using its teeth, spikes, or cleats 464. The metal flap 462 andinferior screw 460 may provide permanent fixation of the triangularimplant 458 to enable permanent distraction of the facet andimmobilization of the joint facilitating permanent fusion of the joint.

FIGS. 64A-C show yet another embodiment of an implant 466. In thisembodiment, a distraction system consists of a central anchoring plug468, an initiating plate 470, and two external plates 472. The twoexternal (superior and inferior) plates 472 may be attached to thelateral masses of a motion segment and may be anchored using screws. Theinitiating plate 470 may then be inserted in the gap 471 between theexternal plates 472 to initiate opening of the plates 472 and the jointand allow for further insertion of the anchoring plug 468. Following theinsertion of this initiating plate 470 and turning or manipulating theplate 470 to open the external plates 472, the central anchoring plug468 may then be advanced into the gap 471 between the external plates472 causing expansion of the plates and distraction and separation ofthe joint.

FIGS. 65A-C show yet another embodiment of an implant 474. In thisembodiment, nitinol hooks 476 may be configured to have a memory. Thehooks 476 may be flattened and inserted through a delivery system 478.The delivery system 478 may be placed in a facet joint. Once insertedwithin the facet, the nitinol hooks 476 may be activated viatemperature, force, or other activation means causing them to assumetheir original (pre-flattened) shape and hook into the opposing facetsurfaces. As the hooks 476 engage the cortical bone of the facetsurfaces, they distract the joint. This separation results in increasedforaminal area and reduced nerve root compression.

FIGS. 66A-C show yet another embodiment of an implant 480. In thisembodiment, a hollow screw sleeve 482 may be placed within the facetjoint. A wedge 484 may then be placed within the hollow screw sleeve 482causing it to expand and distract the joint. Additionally, the screwsleeve 482 may include sharp barbs 486 having a retracted position and aejected position. As the wedge 484 is inserted, the wedge 484 displacesthe sharp barbs 486 causing them to be ejected through the screw sleeve482 and engage the facet surfaces. These barbs 486 may provide acutefixation of the implant 480 to the joint and prevent migration of theimplant 480. The distraction and separation of the joint result inincreased foraminal area and reduced nerve root compression.

FIGS. 67A-C show yet another embodiment of an implant 488. In thisembodiment, a panel anchor implant 488 may be placed within the facetjoint. The implant 488 may include a bolt 490 and collapsible nut 492that is rotationally free from the bolt 490 near the head of the bolt490 and threadably engaged with the bolt 490 near the end opposite thehead. As such, when the bolt 490 is advanced, the distal end of the nut492 is squeezed toward the proximal end of the nut 492 and the nut 492may collapse with an accordion effect. As shown, the compression of thenut 492 results in a taller structure that applies a distraction forceto the opposing facet surfaces. This distraction leads to increasedforaminal area and reduced nerve root compression.

In similar fashion, the embodiment shown in FIGS. 68A-C may collapsecausing distraction of the joint. In lieu of the nut 492 shown in FIGS.67A-C, this embodiment, shows a flat plate 494 that collapses into anaccordion shape.

FIGS. 69A-C show yet another embodiment of an implant 496. In thisembodiment, an implant 496 is placed within the facet joint. The implantcould have a number of shapes and sizes but, in this embodiment, has atension wire 498 that surrounds the implant 496 and is pulled taughtduring implantation. Once the implant 496 is properly positioned, thewire's tension is released. The release of this tension causes the wire498 to return to a preset expanded shape and height that causes theimplant 496 to expand. The expansion of the implant 496 as the wirereturns to its preset, and larger profile, shape causes separation ofthe facet joint. This distraction results in increased foraminal areaand reduced nerve root compression.

Similarly, as shown in FIGS. 70A-C, an implant 500 with an outer housing502 and an internal spring 504 may be positioned in the facet joint withthe wire spring 504 in a tensioned or elongated position. Once properlypositioned, the tension on the spring 504 may be released thuscollapsing the spring 504 and expanding the associated housing 502 ofthe implant 500.

FIGS. 71A-C show yet another embodiment of an implant 506. In thisembodiment screw type implant 506 may be provided and may also includean arm type locking mechanism 508. The locking mechanism 508 may extendfrom all sides of the head of the screw as shown and may be biased in adistal direction. As the screw advances, the locking mechanism 508 mayanchor in the lateral mass of a vertebra. The biased position of the arm508 pressing against the lateral mass may provide a force biasing theimplant 506 against the advancing direction. However, this may causeconstant friction between any newly cut threads in the surfaces of thefacet joint thereby preventing unscrewing or back out of the implant. Inaddition, teeth 509 may be included on the arms 508 and may bite intothe lateral mass further preventing backing out of the implant.

FIGS. 72A-C show yet another embodiment of an implant 510. In thisembodiment, two wedge shape opposing structures 512 are shown separatedby a sloping plane 514. The structures 512 may have a predeterminedrelative position, or a series of predetermined relative positions,where a bolt or screw 516 may be advanced at an angle as shown throughone of the structures 512 and into a predrilled hole of the other 512 tomaintain their relative position. Alternatively, the relative positionsmay not predetermined and a self-drilling screw 516 may be used. Ineither case, the implant 510 may be positioned in the facet joint inminimal profile position and then the two structures 512 may be slidrelative to each other along the sloping plane 514 to expand the implant510 and thus the facet joint. Once the desired position is achieved, thebolt, pin, screw, or other fastenter 516 may be inserted to maintain therelative position of the structures 512.

FIGS. 73A-C show yet another embodiment of an implant 518. In thisembodiment, an implant 518 is configured to be inserted in a collapsedstate. In its non collapsed state, it has a vertical cylindrical profilewith side cutouts 520. When the implant is compressed, the side cutouts520 allow the wall panels 522 to bend out as the height of thecylindrical implant 518 is reduced. These wall panels 522 create ananchor shape that can engage bone structures. This implant 518 may beplaced within the facet join in its flattened, compressed profile. Onceit is positioned correctly, a distraction energy may be applied to theimplant 518 to cause it to expand or decompress. This decompressioncauses the implant 518 to attempt to return to its vertical cylindricalshape. The implant 518 may be made from a resilient elastic materialsuch as nitinol, stainless steel, or other known materials. As theimplant 518 becomes more cylindrical, it pushes against the opposingfacet surfaces. This force causes distraction of the facet joint andresults in increase foraminal area and reduced nerve root compression.

Similarly, as shown in FIGS. 74A-C, the implant 518 may be positioned onits side and the distraction energy may cause the implant 518 tocollapse from its cylindrical shape and expand laterally to distract thefacet joint.

FIGS. 75A-B show yet another embodiment of an implant 524. In thisembodiment, a delivery tool 526 is inserted within the facet joint. Thedistal tip 528 of the delivery tool 526 is shaped to distract the joint.Once the tool 526 is inserted into the facet joint and the desiredamount of distraction is achieved, the distal tip 528 (part that is inthe facet joint) may be detached from the delivery tool 526. In oneconfiguration of this embodiment, the detachable tip 528 would haveteeth, cleats, spikes, or keels 530 to prevent it from migrating withinthe joint once it is detached. In another configuration of thisembodiment, the implant 524 may be anchored in the facet joint byinserting a screw 532 through the superior facet, the implant, and theinferior facet. In both configurations, the detachable tip 526 (implant)may provide permanent distraction of the joint resulting in increasedforaminal area and reduced nerve root compression.

FIGS. 76A-C show yet another embodiment of an implant 534. In thisembodiment, the implant 534 may include a housing 536 with a centralgear 538 turnable by an allen type head 540 or other known attachmentfor turning, such as any known screwdriver heads. Adjacent the centralgear 538 on each side, the implant 534 may include two plates 542slidable in the housing 536 in a direction tangential to the gearsurface. The plates 542 may include teeth 544 engaging the central gear538 such that when the gear 538 turns, the plates 542 slide tangentiallyto the gear 538 and extend beyond an outer surface of the housing 536.As such, the implant 534 may be positioned in a facet joint as shown inFIG. 76A. Once positioned, the gear 538 may be turned thus extending theplates 542 in opposite directions and distracting the facet joint.

FIGS. 77A-C show another embodiment of an implant 546. In thisembodiment a triangular shaped implant 546 in the form of a bent plate548 may be wedged into the facet causing distraction and separation ofthe joint. On one side of the triangular distraction structure 548 is abracket 550 with a screw 552. The screw 552 may be inserted into thelateral mass to provide anchoring of the facet distraction implant 546.The other side of the triangular distraction structure 548 may includeteeth or other features 554 for biting into the associated lateral mass.The implant 546 would provide permanent distraction of the jointresulting in increase foraminal area and reduced nerve root compression.

FIGS. 78A-C show another embodiment of an implant 556. In thisembodiment, the implant 556 may have a tapered shape that is taller atthe posterior aspect relative to the anterior aspect. The implant couldbe tapped in, malleted in, screwed in with threads, or pushed in withhand pressure. Once the implant 556 is positioned correctly, the head558 of the implant 556 (posterior aspect) may be configured to havesharp teeth, spikes, or cleats that can be pushed into the cortical boneof the superior and inferior lateral masses of a motion segment. Theseflaps 558 could be hinged on the posterior aspect of the implant 556 toallow the flaps 558 to be pushed anterior enough to match the irregularcontours of the lateral mass. The implant 556 would provide permanentdistraction of the joint resulting in increase foraminal area andreduced nerve root compression.

FIGS. 79A-C show another embodiment of an implant 560. In thisembodiment, the implant 560 includes a single rotatable cone 562 with ashoulder shaped ledge 564 defining a cam surface 566, the distancebetween the ledge and the bottom of the implant defining a shoulderheight. The shoulder height may vary gradually from low to high and backto low along the circumferential perimeter of the cone 562. In use, theimplant 560 may be initially positioned such that the shoulder portionwith the low ledge height enters the facet joint. Once in position, theimplant 560 may be rotated to cause the higher ledge height to enter thejoint thereby distracting the posterior portion of the joint by causingthe superior articular face to ride upward along the cam surface 566.The implant 560 may then be secured with a screw 568 extending along thelongitudinal axis of the implant.

FIGS. 80A-D show yet another embodiment of an implant 570. In thisembodiment, an implant 570 may include a housing 572 with penetrations574 adapted for ejection of retracted spikes 576. Within the housing572, a wire 578 may be routed between the spikes 576 as shown in FIG.80D. The implant 570 may be inserted into the facet joint while the wire578 is relaxed and the spikes 576 are contained within the folds/curvesin the collapsed wire 578. Once the implant 570 is positioned correctly,the wire 578 may be pulled taught causing the spikes 576 to displaceoutwardly, extending out of the housing 572 and engaging the opposingfacet surfaces with a force. This force may create distraction andseparation of the joint, while the pointed tips of the spikes 576 wouldpenetrate the surface of the facet joint and provide acute fixationpreventing migration of the implant 570. The implant 570 would providepermanent distraction of the joint resulting in increase foraminal areaand reduced nerve root compression.

FIGS. 81A-C show yet another embodiment of an implant 580. In thisembodiment, an implant 580 may include a housing 582 with a cavity 584and penetrations 586 on lateral surfaces extending from the cavity 584through the wall of the housing 582, the penetrations 586 adapted forejection of retracted spikes 588. Within the housing 582, a threadedpiston 590 may be positioned at a distal end and may be adapted fordisplacement through the cavity 584 in the proximal direction. Thepiston 590 may have a torpedo shaped distal end 592 and may engage the abeveled inner surface 594 of the retracted spikes 588. The implant 580may be positioned within a facet joint and when properly positioned, thepiston 590 may be advanced via a turning tool, the torpedo shaped distalend 592 of the piston 590 thus engaging the beveled end 594 of thespikes 588 and advancing them laterally relative to the implant 580 outof the housing 582 with a force and into the face of the facets. Thisforce may create distraction and separation of the joint, while thepointed tips of the spikes 588 would penetrate the surface of the facetjoint and provide acute fixation preventing migration of the implant580.

FIGS. 82A-F show yet another embodiment of an implant 596. In thisembodiment, the implant 596 may include two parallel equal length sidebars 598 with pivoting struts 600 positioned on a pin 602 between thebars 598 at each end. The pivoting struts 600 may include texturedsurfaces 604 on each end and the struts 600 may be pinned to the sidebars 598 through one end. As shown in FIG. 82F, the struts 600 may havelength so as to allow them to be pivoted to lie parallel to one anotherin the plane of the side bars 598. In this position, the implant 596 maybe positioned in the facet joint as shown in FIG. 82A or anterior to thefacet joint as shown in FIG. 82D. Once properly positioned, the struts600 of the implant 596 may be rotated so as to be approximatelyperpendicular to parallel side bars 598 thus separating an inferiorvertebra from a inferior vertebra. It is noted that the generally stoutshape of the struts 600 with relatively broad textured ends 604 mayfacilitate stability preventing the implant 596 from racking back to theparallel condition.

Another variation of this embodiment is shown in FIGS. 83A-B, where aseries of varying height struts 600 are positioned along a shaft. Theentire implant may be placed within a facet joint on its side and then asingle ninety degree turn may position the implant and distract thejoint.

FIGS. 84A-B show yet another embodiment of an implant 606. In thisembodiment, two rotatable cams 608 may be positioned in a facet joint.It is noted that the cams may have a relatively low profile and theproportions in the FIGS. may be exaggerated for purposes of showing theconcept. Once placed in the joint, a distraction/rotation energy may beapplied to the cams causing them to rotate open to reveal two circularhalves of the cam implant. As one half of the implant rotatessuperiorly, it may push the superior vertebra upward creating anincrease in foraminal area and nerve root decompression.

In another embodiment, a kit is provided. As shown in FIGS. 85 and 86,the kit may include a delivery device 610, a chisel 612, severalinternal and external decorticators 614, 616, 618, and a driver assembly620. As shown in FIGS. 87 and 88, the chisel head 622 and shaft 624 maybe provided in two pieces that may be combined with a press fit. Asshown in FIG. 89, the delivery device 610 may be provided in two piecescombinable with a press fit, the first piece being a tubular shaft andfork piece 626 and the second piece being a receiving assembly piece628. As show in FIGS. 90-93, the driver assembly 620 may be provided inseveral pieces including the internal actuator and the implantshaft/arms/handle portion. FIG. 90 shows the shaft/arms/handle,portioncomprising two pieces, the first piece being a shaft with arms 630 andthe second piece being the handle 632. FIGS. 91 and 92 show the internalactuator including a tip 634, a shaft portion 636, an adapter 638, a pin640, and a distractor knob 642. In addition to the elements shown, oneor several implants may be provided as well as an injector as previouslydescribed. Several traditional instruments for use in accessing thesurgical site and closing the surgical site may also be provided.

Referring now to FIGS. 94-116, another embodiment of a tool 800 isshown. FIGS. 94-98 show a chisel 808, a delivery device 804, adecorticator 806, a driver assembly 842, an internal actuator 852, andan injector 902.

As shown in FIG. 95, the delivery device 804 may include a receivingassembly 810 at a proximal end, anchoring forks 812 at a distal end, anda generally tubular shaft 814 defining a longitudinal axis and extendingbetween the receiving assembly 810 and the anchoring forks 812. Thetubular shaft 814 may have an annular shaped cross-section with an innerradius and an outer radius, where the difference between the two radiidefines a thickness of the tubular shaft 814. Some of the features ofthe delivery device 804 will now be described and additional features ofthe delivery device 804 may include those features shown and describedwith respect to delivery device 104. For example, the delivery device804 may include two anchoring forks 812.

The receiving assembly 810 of the delivery device 804 may have agenerally rectangular outer surface defining a generally solid volumewith a bore 811 there through. The bore 811 may be positioned proximalto and in alignment with the tubular shaft 814 and may have an innerradius matching that of the tubular shaft 814 allowing for a smoothtransition of devices from the receiving assembly into the tubularshaft. The receiving assembly 810 may include a seating cavity 813 atits proximal end for receiving and seating of other devices such as thedriver assembly 842 or the injector 902. The seating cavity 813 may bedefined by an outer shell 815 that is substantially flush with the outersurface of the receiving assembly 810. The shell 815 may includeprotrusions or recesses 817 on its inner surface, the protrusions orrecesses 817 corresponding to protrusions or recesses on other devices.As such, these protrusions or recesses 817 may provide for a detentrelationship between the delivery device 804 and other devices. Therectangular outer surface of the receiving assembly 810 may have a longside and a short side. The long side may be oriented parallel to a lineconnecting the forks 812 in turn aligning the seating cavity 813 withthe forks 812. As such, devices used with the delivery device 804 may beproperly aligned relative to the forks 812 by positioning and seatingthem in the seating cavity 813. Additionally shown on the outer surfaceof the receiving assembly 810 is a decorticator release button 819. Asshown, the button 819 may include slots on either side creating acantilevered tab condition for the button 819. As such, the button 819may deflect about its proximal end when depressed. The button 819 mayalso include recesses or bumps on its surface for gripping. The button819 may extend beyond the distal end of the receiving assembly 810 andmay include an upwardly extending ridge 821. The ridge 821 may be shapedand adapted to engage the decorticator 806 as described in greaterdetail below. There may be one button 819, or two buttons 819, one oneach face of the receiving assembly 810. Any number of buttons 819 maybe included, for example in the case of a varying shaped receivingassembly, 810.

Referring to FIG. 94, the chisel 808 may have a generally cylindricalcross-section forming a shaft 828. The shaft 828 may have a radiussubstantially equal to the inner radius of the tubular shaft 814 portionof the delivery device 804 allowing for slidable insertion of the chisel808 within the delivery device 804. Alternatively, the radius of theshaft 828 may be smaller than the inner radius of the tubular shaft 814providing for more play and adjustability of the chisel 808 and deliverydevice 804 relative to one another. The chisel 808 may include a singleor doubly chamfered tip 830 at a distal end or may have a coped distalend. The chisel 808 may include a head or, in contrast to the chisel 108described with respect to FIG. 1, the chisel 808 may not include a headas shown in FIG. 94. The chisel 808 may have an overall length slightlylarger than the delivery device 804 so as to allow the chisel to bemanipulated by its proximal end when sleeved within the delivery device804. Additional features of the chisel 808 may include those featuresshown and described with respect to chisel 108. For example, similar tothe chisel shown and described with respect to FIG. 1A, the chisel 808may also include a longitudinally extending lumen 131. A more detailedview of the chisel 808 and its chamfered tip 830 may be seen in FIG.94A. As shown, the chisel 808 may include a circumferential bevel at itsproximal end opposite the chamfered tip 830.

In comparison to the use described with respect to FIG. 5 above, it isnoted that the chisel 808 may allow the option of inserting the chisel808 prior to the delivery device 804 and sleeving the delivery device804 over the chisel 808. This is in contrast to the chisel 108, with thehead 132, where the head 132 prevents the delivery device 104 from beingsleeved over the chisel 108. As such, the facet joint may be distractedby the chisel 808 initially allowing for smoother insertion of thedelivery device 804. Upon placement and proper positioning of thedelivery device 804, the chisel 808 may then be removed. Those of skillin the art will understand and appreciate that a chisel with a removablehead may also be provided and may allow for either order of insertion ofthe delivery device 804 and chisel 808 and the removable head, oncereplaced, may then be used to more readily manipulate and properlyposition the chisel 808.

In some embodiments, the forks 812 at the distal end of the deliverydevice 804 may have a bull nose tip as shown in FIG. 95A. This is incontrast to the relatively sharp tip shown in FIGS. 2-4 with respect toforks 112. The use of a chisel 808 without a handle, which may allow forinsertion of the chisel 808 prior to the delivery device 804, may, inturn, allow for this bull nose tip because the facet joint may bedistracted prior to insertion of the delivery device 804.

Referring again to FIG. 95, the decorticator 806 may have a tubularshaft portion 834, an abrasive distal end 836, and a handle 838 at aproximal end. The tubular shaft 834 may have an inner radiussubstantially equal to the outer radius of the tubular shaft 814 of thedelivery device 804 and may allow for sliding movement of thedecorticator 806 along the length of the delivery device 804 androtationally around the delivery device 804. In some embodiments, theinner radius of the tubular shaft 834 may be slightly or substantiallylarger than the outer radius of the tubular shaft 814 of the deliverydevice allowing for more freedom of movement of the decorticator 806.The abrasive distal end 836 may include serrated teeth as shown, or mayinclude a more flat annular surface with a gritty surface. The handle838 may include a generally cylindrically shaped knob with a grippingsurface along its peripheral edge. The handle 838 may also include acavity on its proximal face for receiving a distal end of thedecorticator release button 819. The cavity may thus create an innercylindrical surface opposite the gripping surface of the handle 838. Theinner cylindrical surface may be beveled or may include a groove forreceiving the tip of the ridge 821 extending upwardly from the releasebutton 819. As such, where the release button 819 is in its naturalstate, the ridge 821 may project into the groove or opposed to thebeveled surface of the handle 838 preventing the decorticator from beingadvanced distally. Where the release button 819 is depressed, the ridgemay be removed from the groove or beveled surface allowing thedecorticator to advance freely. Additional features of the decorticator806 may include those features shown and described with respect todecorticator 106. For example, the decorticator 806 may alternatively beseparate from the delivery device 804 and may be slidably insertedwithin the delivery device 804 similar to that shown and described withrespect to FIG. 4 or FIGS. 6A-6C.

Referring now to FIGS. 99-101, the delivery device 804 and a driverassembly 842 are shown. As shown in FIG. 99, the driver assembly 842includes a handle 844, an implant shaft 846, and implant holding arms848. The driver assembly 842 shown is holding an implant 154. The handle844 of the driver assembly 842 may have an outer surface defining agenerally rectangular volume with a bore 843 there through. The bore 843may have an inner diameter substantially equal to the inner diameter ofthe implant shaft 846 allowing for a smooth transition of devicespassing through the driver assembly 842. The handle 844 may have anecked down portion 845 at its distal end. The necked down portion 845may have protrusions or recesses 847 on its outer surface correspondingto respective protrusions or recesses 817 on the inner surface of theshell 815 of the receiving assembly 810 on the delivery device 804. Assuch, and as shown in FIGS. 100 and 101, the driver assembly 842 may besleevably positioned within the delivery device 804 to deliver animplant 154/854 to the facet joint. When fully advanced as shown in FIG.101, the handle 844 may be seated securely in the seating cavity 813 ofthe receiving assembly 810 and anchored with a detent relationship.Additional features of the driver assembly 842 may include thosefeatures shown and described with respect to driver assembly 142.

A more detailed view of the implant holding arms 848 is shown in FIG.99A. As shown, the implant holding arms 848 may include a chamfered tip.Additional features of the arms 848 may include features similar tothose shown and described with respect to arms 148 in relation to FIG.11. For example, the inside surface of the arms 848 may include alongitudinal ridge 862 extending the length of the arms 848. The arms848 may also include a bull nose engagement feature 858 extendingtransverse to the longitudinal axis of the implant shaft 846 along theinside face of the arm 848. Where the arms 848 are engaged with andholding the implant 154/854, the longitudinal ridges 862 of each arm 848may be positioned between upper and lower planar members of the implant154/854 and the bull nose engagement features 858 may be positioned inthe U-shaped receiving feature slots on the lateral edges of the implant154/854.

In contrast to the driver assembly 142 described above, in the presentembodiment shown in FIGS. 102-105, the internal actuator 852 may be aseparate device from the driver assembly 842. That is, while theinternal actuator 852 may still function by passing longitudinallythrough the driver assembly 842, the internal actuator 852 may be aseparate device with its own handle 853. The internal actuator 852 mayinclude a longitudinal shaft 855 and an internal rod 857. Thelongitudinal shaft 855 may be cylindrically shaped with an annularcross-section. The shaft 855 may have an outer diameter substantiallythe same as or smaller than the inner diameter of the implant shaft 846of the driver assembly 842. The-shaft 855 may extend from the handle 853proximally to a distal end. The internal rod 857 may be positionedwithin the shaft 855 and also may extend from the handle 853 to a distalend. The internal rod 857 may include an engagement feature 859 at itsdistal end for engaging and holding the implant distractor 850. Thisengagement feature 859 may be any shape and provide for any engagementknown in the art from a hex, allen, phillips, star, square, sleeve, orother connection capable of transmitting longitudinal and/or rotationalforces from the internal rod 857 to the implant distractor 850. Asshown, in one embodiment, the engagement feature 859 includes a collettype device that is described in more detail with respect to FIG. 109below. As shown, the internal rod 857 may sleevably receive the implantdistractor 850. The internal rod 857 may be sleevably positioned withinthe longitudinal shaft 855, such that when the longitudinal shaft 855 isin an advanced position over the end of the internal rod 857, thelongitudinal shaft 855 causes a clamping force of the collet to restrainthe implant distractor 850 against being dislodged from the collet. Eachof the shaft 855 and the internal rod 857 may engage the handle 853 attheir respective proximal ends. The handle 853 may be used to retractthe longitudinal shaft 855 along the length of the internal rod 857thereby exposing the collet and reducing the clamping force. As such,when the longitudinal shaft 855 is in a retracted position, an implantdistractor may be inserted into and/or removed from the collet.

As shown in FIGS. 104 and 105, the handle 853 may be acylindrical/spherical handle or a T-type handle. Referring to FIG. 104,the cylindrical/spherical handle may include an outer cylindricalportion 861 capped at a proximal end by a first spherical portion 863,the first outer cylindrical portion 861 being open at a distal end. Thehandle 853 may also include an inner cylindrical portion 865 capped at adistal end by a second spherical portion 867, the inner cylindricalportion 865 being open at a proximal end. As shown, the proximal openend of the outer cylindrical portion 861 may be positioned opposing thedistal open end of the inner cylindrical portion 865 and the innercylindrical portion 865 may sleevably slide within the outer cylindricalportion 861. The handle 853 may further include a collar 869 integralwith the second spherical portion 867, positioned concentrically to eachof the outer and inner cylindrical portions 861, 865 and extendingdistally away from the second spherical portion 865. Those of skill inthe art will understand and appreciate that the collar 869 could alsoextend in a proximal direction. In either case, the shaft 855 of theinternal actuator 852 may be connected to the distal end of the collar869 and extend distally there from. The internal rod 857 of the internalactuator 852 passing proximally through the shaft may sleevablypenetrate the collar 869 and the second spherical portion 867, extendthrough the handle 853 to the inner/distal surface of the firstspherical portion 863, and be coupled thereto. In addition, the firstand second spherical portions 863, 867 may have a biasing mechanism 871positioned between them in the form of a spring, balloon, or other forceinducing device. Those of skill in the art will understand andappreciate that the spherical portions 863, 867 could be flat, concave,or otherwise shaped and are not limited to spherical shaped caps.

In use, as understood by a review of FIGS. 103 and 104, a user mayinsert the internal actuator 852 through the driver assembly 842, whichis positioned and seated in the delivery device 804. The internalactuator 852 may be used to advance and position the implant distractor850 for advancement into the implant. Once properly positioned, theinternal actuator 852 may be rotated via the handle 853 to advance theimplant distractor 850. In the cases of other implant distractors, thehandle 853 may be otherwise manipulated to advance the implantdistractor. Once the implant distractor is advanced and the implant isdistracted, a user may compress the first and second spherical portions863, 867 toward one another against the force of the biasing mechanism871 (e.g. by squeezing the handle with their hand). The innercylindrical portion 865 of the handle 853 may retract relative to theouter cylindrical portion 861 causing the longitudinal shaft 855 also toretract relative to the to the outer cylindrical portion 861. Thisretracting motion relative to the internal rod 857 may cause the distalend of the longitudinal shaft 855 to be retracted and expose the colleton the distal end of the internal rod 857. As such, the clamping forceof the collet on the implant distractor 850 may be reduced allowing forremoval of the internal actuator 852, while leaving the implantdistractor 850 behind and in place in the implant. It is noted that theshaft portion 855 of the implant distractor 852 may include a keyway forengagement with the inner surface of the implant shaft 846 of the driverassembly 842. As such, the shaft 855 of the internal actuator 852 may beprevented from rotating relative to the internal rod 857.

Referring now to FIG. 105, the T-type handle may have a cylindrical,rectangular, square, or other transverse cross-section, with alongitudinal axis extending generally perpendicular to the longitudinalaxis of the internal rod 857 and shaft 855 and forming a T-shape. Thelongitudinal cross-section of the handle 853, as depicted in FIG. 105,may include a proximal portion 873 and a distal portion 875 connected atone end and separated by a gap 877. The proximal portion 873 may be arelatively thick portion and the distal portion 875 may be relativethin. As such, the handle 853 may be squeezable and may provide abiasing force which works to maintain the gap 877 between the distal andproximal portions 873, 875. The handle 853 may also include a generallycylindrical or conical collar 879 positioned near the middle of thehandle 853 along its longitudinal length. The collar 879 may bepositioned parallel to and concentrically with the internal rod 857. Theshaft portion 855 of the internal actuator 852 may extend distally fromthe distal end of the collar 879. The internal rod 857 may sleevablypenetrate the collar 879 and the distal portion 875 of the handle 853and may further be coupled to the proximal portion 873 of the handle 853in a cylindrical bore 881. A stop may be provided to prevent theinternal rod 857 from passing proximally through the proximal portion873 of the handle 853. This may be in the form of a cap on the proximalportion 873 of the handle 853 covering the bore 881, or the bore 881 maynot pass all the way through the proximal portion 873 of the handle 853.Alternatively, the internal rod 857 may be secured within the bore.

In this embodiment, as understood by a review of FIGS. 103 and 105, theinternal actuator 852 may be inserted through the driver assembly 842and the implant distractor 850 may be advanced in the same or similarfashion as that described with respect to the internal actuator 852 ofFIG. 104. When the internal actuator is ready for removal, a user maycompress the proximal 873 and distal 875 portions of the handle 853toward one another against the biasing force by squeezing the handle853. The distal portion 875 of the handle 853 may retract relative tothe proximal portion 873 causing the longitudinal shaft 855 also toretract relative to the proximal portion 873. This retracting motion ofthe longitudinal shaft 855 relative to the internal rod 857 may causethe distal end of the longitudinal shaft 855 to be retracted and exposethe collet on the distal end of the internal rod 857. As such, theclamping force of the collet on the implant distractor 850 may bereduced allowing for removal of the internal actuator 852, while leavingthe implant distractor 850 behind and in place in the implant.

Still another embodiment of a handle 853 is shown in FIGS. 106-108. Inthis embodiment, a gripping mass 883 with a knob 885 is shown. A knob885 is positioned on the proximal end of the internal rod 857 via a bore887. The knob 885 may be affixed against relative rotation with theinternal rod 857. The gripping mass 883 may include a generallyrectangular mass spaced from the knob 885 along the internal rod 857 andincluding a bore 889 for the internal rod 857 to pass there through. Thebore 889 may sleevably receive the internal rod 857. The gripping mass883 and the internal rod 857 may form the shape of a T and the grippingmass 883 may be affixed to the proximal end of the longitudinal shaft855. The gripping mass 883 may be held apart from the knob 885 along theinternal rod 857 by a biasing mechanism 891 in the form of a spring,balloon, or other known device.

The implant distractor 852 shown in FIGS. 106 and 107 may be insertedthrough the driver assembly similar to that shown and described withrespect to FIG. 103 above. The implant distractor may be rotated orotherwise manipulated to advance the implant distractor 850. Once theimplant distractor is positioned, a user may grip the gripping mass 883with their fingers and allow the knob 885 to settle into the palm oftheir hand. The user may then squeeze the knob 885 toward the grippingmass 883 depressing the biasing mechanism 891 between the two andretracting the longitudinal shaft 855 along the internal rod 857 andcausing the distal end of the longitudinal shaft 855 to be retracted andexpose the collet on the distal end of the internal rod 857. As such,the clamping force of the collet on the implant distractor 850 may bereduced allowing for removal of the internal actuator 852, while leavingthe implant distractor 850 behind and in place in the implant.

As shown in more detail in FIG. 108, the engagement feature 859 at thedistal end of the internal rod 857 may take the form of a collet 893 forholding the implant distractor 850. The collet 893 may be affixed to thedistal end of the internal rod 857 and may be adapted to hold theimplant distractor 850. Those of skill in the art will understand andappreciate that the collet 893 may be permanently affixed to the distalend of the internal rod 857 or may be interchangeably coupled thereto.Those of skill will further understand that several collet and chuckarrangements are known in the tool industry for receiving bits or otherdevices, which are within the scope of the invention. As shown, thecollet 893 is extending slightly out of the distal end of thelongitudinal shaft 855 and is thus in position to receive an implantdistractor or is in position to allow removal of the internal actuator852 after placement of the implant distractor 850.

The collet 893, positioned on the distal end of the internal rod 857 andshown in FIG. 108, may be seen more clearly in FIG. 109. In someembodiments as shown, the collet 893 may include a generally cylindricalbody member 895 with four receiving fingers 897 equally spaced around abore 899. The body member 895 may be the internal rod 857 or may be aseparate piece which is affixed to the end of the internal rod 857. Eachof the fingers 897 may extend distally from the body member 895 and beseparated by slots 901. The fingers 897 may extend laterally acrossapproximately one quarter of a cylinder wall and may have constantthickness as they extend from the body 895. Near the distal end of thefingers 897, the outer surface of each finger 897 may be tapered up todefine a thicker finger thickness and then tapered back down at the verydistal end. As such, when the longitudinal shaft 855 is advanced overthe collet 893, the tapered outer surface causes the fingers 897 todeflect inward creating a clamping force on the implant distractorpositioned within the collet. Those of skill in the art will understandand appreciate that the collet may include as few as two fingers 897 andmay include any number of fingers. The bore 899 defined by the fingers897 may extend into the cylindrical body 895 a specified distance. Atthe transition 903 between the body 895 and fingers 897, which locationis defined by the depth of the slots 901, the transition 903 defines aneck where a wider body portion 895 necks down to the finger portion897.

Referring now to FIG. 110, a cross-section of the longitudinal shaft 855is shown. As shown, the longitudinal shaft 855 may include an internalbore 905 at its distal end for receiving the internal rod 857 and thecollet 893. The internal bore 905 may be the same or similar to the boreextending the length of the longitudinal shaft 855. The distal end ofthe bore 905 may include an outwardly beveled edge for riding along thebeveled outer surface of the collet 893 when the longitudinal shaft isadvanced and creates a clamping force on the collet. 893

Referring now to FIGS. 111-113 an implant distractor 850 is shown. Theimplant distractor 850 may be a generally narrow element having acylindrical body 907 which tapers to a point at a distal end. At aproximal end 864, the implant distractor 850 may have a squarecross-section and may include a circumferential groove 909 positionedjust proximal to the distal end of the implant distractor 850. Thisgroove 909 may correspond to a protrusion or spring ball on the innersurface of the engagement feature 859 of the internal actuator 852forming a detent connection between the engagement feature 859 and theimplant distractor 850. Alternatively or additionally, where a collet893 is used the groove 909 may engage a feature inside the collet 893 soas to prevent the implant distractor 850 from inadvertently dislodgingfrom the collet 893. The square proximal end 864 may be isolated fromthe cylindrical body 907 by an annular stop ring 911. The annular stopring 911 may have an outer radius similar to the inner radius of thedriver assembly 842. This stop ring 911 may allow for sliding movementof the implant distractor 850 through the implant shaft 846 of thedriver assembly 842. The stop ring 911 may prevent over advancement ofthe implant distractor 850 by creating an abutting relationship betweenthe distal face of the stop ring and the proximal edge of the implant.

As best shown in FIGS. 112 and 113, the implant distractor 850 mayinclude a generally continuous coil-shaped thread feature 866. Thethread feature 866 may have an abrupt proximal end 913 just distal tothe annular stop ring 911 and may continue to the distal end of theimplant distractor 850. The thread feature 866 may gradually terminateat the distal end of the implant distractor 850 by gradually minimizingits cross-sectional profile. This may occur over several turns or insome embodiments, this transition may occurs within a 180 degree turn.In other embodiments, this transition occurs between a 90 degree and a180 degree turn. While the thread feature 866 is generally continuous,as shown in FIG. 112, the thread feature 866 may be interrupted by atleast one cross-cut 915 at one or more locations along the threadedfeature 866. In one embodiment, as shown in FIG. 112, a single cross-cut915 may be positioned just proximal to the distal end. This cross-cut915 may be positioned approximately 180 degrees out of phase from theabrupt proximal end 913 of the thread feature 866. Both the cross-cut915 and the abrupt proximal end 913 may provide for interlockingengagement of the implant distractor 850 with the implant 154/854 andthus prevent backing out of the implant distractor 850.

Turning now to FIGS. 114-116, an injector 902 and delivery device 804are shown. As shown in FIG. 114, the injector 902 may include alongitudinal delivery shaft 917, a seating feature 919, a grippingfeature 921, and a plunger 923 with a handle 925. The longitudinaldelivery shaft 917 may have any cross-section and may have across-sectional size adapted to fit within the delivery device 804. Thelongitudinal shaft 917 may have an opening 927 on its distal end fordirecting bone paste toward the lateral mass portion of a facet joint.In another embodiment, the shaft 917 may include two opposing openings927 or a series of openings 927 on its distal end. The openings 927 maybe positioned to penetrate the wall of shaft 917. The seating feature919 may include a rectangular or other shaped block positioned aroundthe shaft 917 and sized and shaped to engage the seating recess 813 inthe receiving assembly 810 of the delivery device 804. As shown, theseating feature 919 may include a necked down portion on its distal endwhich may be received by the shell portion 815 of the receiving assembly810. As with the driver assembly 842, the seating feature 919 of theinjector 902 may include protrusions or recesses 929 corresponding toprotrusions or recesses 817 on the inner surface of the shell 815allowing for a detent relationship for securing the injector 902 to thedelivery device 804. The seating feature 919 may have an orientationperpendicular to the orientation of the openings 927 at the distal endof the shaft 917 such that once in position, the openings 927 may directbone paste or other material perpendicular to the facet joint surfacealong the spine and adjacent to the facet joint. The gripping feature921 may be any shape and may be affixed to the proximal end of the shaft917. This feature 921 may include a gripping profile on its distal facefor receiving 1, 2, or any number of fingers on one or either side ofthe shaft 917. The gripping feature 921 may allow the user to grasp theinjector 902 and squeeze the plunger handle 925 toward the grippingfeature 921 thus advancing the internal piston and ejecting the bonepaste or other material.

As shown in FIG. 116, the injector 902 may be sleevably inserted intothe delivery device 804 and advanced such that the distal end of theshaft 917 is positioned between the forks 812. The seating feature 919may be secured with the detents thus orienting the openings 927 in theshaft 917 perpendicular to the forks 812. The plunger handle 925 may besqueezed relative to the gripping feature 921 and bone paste or othermaterial may be injected toward the facet joint site. Additionalfeatures not mentioned may be included as shown and described withrespect to the injector 202. For example, the plunger 923 may include aseal.

Turning now to FIGS. 117-120, another embodiment of an implant 854 isshown. The implant 854 may include upper 868 and lower 870 members. Themembers 868, 870 may be generally planar and may also be generallyrectangular. Each of the upper 868 and lower 870 members may include aproximal edge 872, a distal edge 874, and a pair of parallel lateraledges 876 extending longitudinally between the distal edges 874 and theproximal edges 872. In the present embodiment, as shown in FIGS.117-120, the distal edges 874 of the members 868, 870 may each includeinterlocking scissor features 931. As shown, a portion of the membernear the distal edge 874 of each member may be radiused and bend in thedirection of the opposing member. As shown in FIGS. 118 and 119, aninterlocking slot 933 may be provided extending laterally halfway acrossthe member just proximal to the distal edge 874 and within the radiusedbend portion of the member. In one embodiment, the width of the slot 933may be generally similar in width to the distance from the distal edge874 to the slot 933. The slot 933 in the upper member 868 and lowermember 870 may be positioned on the same side such that when one of themembers is inverted, the slots may engage one another as best shown inFIGS. 120. The upper and lower members 868, 870 may be welded togetheralong an upper seam 935, lower seam 937, and/or a front seam 939. Onceinterlocked, the planar members 868, 870 may be biased by the connectionat their distal edges 874 to be generally parallel to each other, theinner faces 878 of the planar members 868, 870 facing each other in anopposed fashion and abutting or nearly abutting each other. It is notedthat, while the interlocking slot 933 is shown extending anatomicallylaterally from the anatomical medial side of the upper member 868 andextending anatomically medially from the anatomical lateral side of thelower member 870, the orientation of this slot may be reversed. Thisreversed orientation may provide resistance to shearing of the upper 868and lower 870 members relative to one another upon receiving the implantdistractor. That is, as the implant distractor is advanced into theimplant 854, it may be rotating in a clockwise fashion. When engagingthe implant 854, this rotation may have a tendency to cause the uppermember 868 to shift laterally and to cause the lower member to shiftmedially. The reversed orientation may resist this shifting.

Additional features of the implant 854 may include those features shownand described with respect to implant 154. For example, a guide feature884 may be included as shown. As an additional example, threaded slots888 may also be included in each planar member 868, 870 for receivingthe coil-shaped thread feature 866 on the implant distractor 850. In thepresent embodiment, one of the threaded slots 888 on one of the members868, 870 may be a truncated threaded slot 941 for engaging the cross-cutthread 915 or the abrupt proximal end 913 of the coil-shaped threadfeature 866 and preventing unscrewing or backing out of the implantdistractor 850 once advanced and positioned. As shown in FIGS. 118 and119, each member 868, 870 may have one truncated threaded slot 941 forengaging either a cross-cut thread 915 or the abrupt proximal end 913 ofthe thread feature 866. As such, the implant distractor 850 may be heldin place and prevented from backing out by both the upper and lowermember 868, 870.

Those of skill in the art will understand and appreciate that theimplant embodiments depicted herein may be made of several types ofbiocompatible materials including stainless steel, titanium, ceramics,nitinol, polymers, and other materials known in the art.

Referring now to FIGS. 121-128, another embodiment of a tool 1000 isshown. FIG. 121 shows a chisel 1008, a delivery device 1004, adecorticator 1006, a driver assembly 1042, an internal actuator 1052, aninternal rod 1057 for the internal actuator 1052, an injector 1102, anda gripping tool 1001.

Referring to FIG. 122, the chisel 1008 may have a generally cylindricalcross-section forming a shaft 1028. The shaft 1028 may have a radiussubstantially equal to the inner radius of the tubular shaft portion1014 of the delivery device 1004 (shown in FIG. 123) allowing forslidable insertion of the chisel 1008 within the delivery device 1004.Alternatively, the radius of the shaft 1028 may be smaller than theinner radius of the tubular shaft 1014 providing for more play andadjustability of the chisel 1008 and delivery device 1004 relative toone another. In some embodiments the shaft 1028 may have a radiusranging from approximately 1 mm to approximately 8 mm. In otherembodiments, the shaft 1028 may have a radius of approximately 4 mm. Thechisel 1008 may include a single or doubly chamfered tip 1030 at adistal end or may have a coped distal end or a combination of coping andchamfering. The tip 1030 may include a roughened surface on one or moresides to aid in anchoring or docking the chisel in the facet joint.Additionally, this roughened surface may allow for roughening ordecorticating the inner surfaces of the facet joint. The tip 1030 mayhave a length 1037 adapted to extend substantially across the facetjoint. As such, the length 1037 may be any length corresponding to thedistance across a given facet joint. In one embodiment, the length 1037may fall within a range from approximately 5 mm to approximately 35 mmlong. In another embodiment, the length may fall within a range fromapproximately 10 mm to approximately 30 mm. In yet another embodiment,the length may fall within a range from approximately 14 mm toapproximately 29 mm.

The chisel 1008 may, include a head or, in contrast to the chisel 108described with respect to FIG. 1, the chisel 1008 may not include a headas shown in FIG. 122. The chisel 1008 may have an overall lengthslightly larger than the delivery device 1004 so as to allow the chisel1008 to be manipulated by its proximal end when sleeved within thedelivery device 1004. The chisel 1008 may have a coped proximal end 1033as shown. The cope 1033 may occur on one or more sides of the chisel1008 and may allow for easier grasping of the chisel 1008 with othertools. For example, a slap hammer may be used to grasp the chisel 1008and hammer back on the chisel 1008 during removal. Additionally, ahemostat may be used to grasp, manipulate, or otherwise distance thesurgeon's hand and/or body from the proximal end of the chisel 1008 tofacilitate taking of x-rays. Further shown in FIG. 122 is a horizontalbore 1035 for receiving a shaft portion of the gripping tool 1001. Assuch, the gripping tool 1001, may be inserted into the horizontal bore1035 in the proximal end of the chisel 1008 forming a T-shaped grip thatmay be used to manipulate the chisel 1008 and/or remove the chisel 1008.

Additional features of the chisel 1008 may include features of the otherchisels shown and described herein. For example, similar to the chiselshown and described with respect to FIG. 1A, the chisel 1008 may alsoinclude a longitudinally extending lumen. In this embodiment, the chisel1008 may allow for insertion of a scope or flushing fluids as discussedabove. Also, the chisel 1008 may allow for diagnostic processes. Thatis, the chisel 1008 may be positioned in a facet joint and a diagnosticballoon catheter may be inserted through the lumen of the chisel 1008 todistract the joint. Feedback from a consciously sedated patient mayallow a provider to obtain information relating to symptom relief. Assuch, one or more joints may be reviewed diagnostically and thus mayallow for treatment of one or several problematic joints with confidencethat the proper joints are being treated. An exemplary diagnosticballoon catheter and method suitable for this application is describedin U.S. patent application Ser. No. 12/110,548, entitled CervicalDistraction Method, filed on Apr. 28, 2008, the contents of which arehereby incorporated by reference herein.

In comparison to the use described with respect to FIG. 5 above, it isnoted that the chisel 1008 may allow the option of inserting the chisel1008 prior to the delivery device 1004 and sleeving the delivery device1004 over the chisel 1008. This is in contrast to the chisel 108, withthe head 132, where the head 132 may prevent the delivery device 104from being sleeved over the chisel 108. As such, the facet joint may bedistracted by the chisel 1008 by inserting the chisel 1008 and tapping,hammering, or otherwise advancing the chisel 1008 into the facet joint.Once in place, the delivery device 1004 may be inserted. Upon placementand proper positioning of the delivery device 1004, the chisel 1008 maythen be removed. In another embodiment, a chisel with a removable headmay also be provided and may allow for either order of insertion of thedelivery device 1004 and chisel 1008. In the case of inserting thechisel 1008 first, the removable head may initially be removed from thechisel 1008. Once replaced, the removable head may then be used to morereadily manipulate and properly position the chisel 1008.

In some embodiments, the forks 1012 at the distal end of the deliverydevice 1004 may have a bull nose tip as shown in FIG. 123. This is incontrast to the relatively sharp tip shown in FIGS. 2-4. The use of achisel 1008 without a handle, which may allow for insertion of thechisel 1008 prior to the delivery device 1004, may, in turn, allow forthis bull nose tip because the facet joint may be distracted prior toinsertion of the delivery device 1004.

In still further embodiments, the chisel 1008 may be radiolucent. Thatis, the chisel may be made of plastic or other material not reflected byan x-ray. This may allow for lateral fluoroscopy to more readily showthe position of a chisel, delivery device, or other device in a contralateral facet joint without obstructing the view.

As shown in FIG. 123, the delivery device 1004 may include a receivingassembly 1010 at a proximal end, anchoring forks 1012 at a distal end,and a generally tubular shaft 1014 defining a longitudinal axis andextending between the receiving assembly 1010 and the anchoring forks1012. The tubular shaft 1014 may have an annularly shaped cross-sectionwith an inner radius and an outer radius, where the difference betweenthe two radii defines a thickness of the tubular shaft 1014. Thedelivery device may and all of the associated elements may be any sizeand may be adapted for the particular anatomy being addressed. In someembodiments, the outer radius of the tubular shaft 1014 may range fromapproximately 2 mm to approximately 8 mm. In some embodiments, thetubular shaft 1014 may have an outer radius of approximately 5 mm.

Some of the features of the delivery device 1004 will now be describedand additional features of the delivery device 1004 may include featuresof other delivery devices shown and described herein, such as, forexample, the anchoring forks 1012.

The receiving assembly 1010 of the delivery device 1004, shown in FIGS.123 and 123A, may have a generally smooth contoured outer surface thattransitions from a generally rectangular cross-section at a proximal endto a narrower and generally circular cross-section at a distal end, thereceiving assembly defining a volume with a bore 1011 extending therethrough. The bore 1011 may be positioned proximal to and in alignmentwith the tubular shaft 1014 and may have an inner radius matching thatof the tubular shaft 1014 allowing for a smooth transition of devicesfrom the receiving assembly 1010 into the tubular shaft 1014. As bestshown in FIG. 123A, the tubular shaft 1014 may engage the receivingassembly 1010 with a dove tail connection 1017 around the periphery ofthe proximal end of the tubular shaft 1014. Also shown in FIG. 123A is atapered entrance 1019 to the bore 1011 at its proximal end to facilitateease of entry of other devices. The receiving assembly 1010 may includeone or more seating cavities 1013 opening in a proximal direction forreceiving and seating of other devices such as the driver assembly 1042or the injector 1102. These seating cavities 1013 may be defined by anouter shell 1015 that is substantially flush with the outer surface ofthe receiving assembly 1010. The seating cavities 1013 may be positionedradially adjacent to the bore 1011. In the present embodiment, twoseating cavities are shown adjacent to the bore 1011 and on oppositesides of the bore 1011. While not shown, the shell 1015 may includeprotrusions or recesses on its inner surface, the protrusions orrecesses corresponding to protrusions or recesses on other devices. Assuch, these protrusions or recesses may provide for a detentrelationship between the delivery device 1004 and other devices.Alternatively or in addition to the protrusions or recesses, the seatingcavities 1013 may have an inner surface that tapers such that thecross-section of the cavity 1013 also tapers from a relatively broadcross-section at its proximal end to a relatively narrow cross-sectionat its distal end. As such, these seating cavities 1013 may provide fora friction fit between the receiving assembly 1010 and another device,where the other device may have a male portion with a shapecorresponding to the shape of the seating cavity 1013. Thecross-sectional shape of the cavities 1013 may include a relativelytrapezoidal shape with a concave base as shown, the base bordering alongthe perimeter of the bore 1011. Any cross-sectional shape includingsquare, rectangular, triangular, circular, or a more undefined randomshape may be used.

The generally rectangular cross-section of the proximal portion of thereceiving assembly 1010 may have a long side and a short side. The longside may be oriented parallel to a line connecting the forks 1012 inturn aligning the seating cavities 1013 with the forks 1012. As such,devices used with the delivery device 1004 may be properly alignedrelative to the forks 1012 by positioning and seating them in theseating cavities 1013.

Just distal to the receiving assembly 1010, a circumferential groove1021 is shown on the tubular shaft 1014. The groove 1021 may be adaptedto aid in securing the decorticator (not shown), further describedbelow. Alternatively, the groove 1021 may be adapted for gripping by ahemostat or other tool. For example, a hemostat may be used to hold thedelivery device 1004 where the delivery device 1004 is being held inposition for an x-ray and the practitioner or other user may beattempting to distance their hand from the x-ray field.

Also shown in FIG. 123 are the forks 1012. These forks 1012 may beadapted to anchor the delivery device 1004 in the facet joint. As such,similar to the chisel 1008, the forks 1012 may include a roughened ortoothed surface. Additionally, the distal ends of the forks 1012 may bebeveled to aid in advancing the tool through tissues and avoid snags.Moreover, the length 1023 of the forks 1012 may be adapted to extendsubstantially across the facet joint. As such, in one embodiment, thelength 1023 of the forks 1012 may range from approximately 5 mm toapproximately 35 mm. In another embodiment, the length 1023 may rangefrom approximately 10 mm to approximately 30 mm. In still anotherembodiment, the length 1023 may range from approximately 14 mm toapproximately 29 mm.

Referring now to FIG. 124, the decorticator 1006 may have a tubularshaft portion 1034, an abrasive distal end 1036, and a handle 1038 at aproximal end. The tubular shaft 1034 may have an inner radiussubstantially equal to the outer radius of the tubular shaft 1014 of thedelivery device 1004 and may allow for sliding movement of thedecorticator 1006 along the length of the delivery device 1004 androtationally around the delivery device 1004. In some embodiments, theinner radius of the tubular shaft 1034 may be slightly or substantiallylarger than the outer radius of the tubular shaft 1014 of the deliverydevice 1004 allowing for more freedom of movement of the decorticator1006. In some embodiments, the outer radius of the decorticator mayrange from approximately 2 mm to approximately 10 mm. In anotherembodiment, the decorticator may have an outer radius of approximately 6mm.

The abrasive distal end 1036 of the decorticator 1006 may includeserrated teeth 1037 as shown, or may include a more flat annular surfacewith a gritty surface. In the embodiment shown in FIG. 124, the distalend of the tubular shaft portion 1034 is chamfered and the serratedteeth 1037 are located on the distal most end of the chamfered endallowing for a more directed and controllable decorticating process. Assuch, the decorticator 1006 shown is well suited for the intra facetprocess reflected by many of the embodiments described herein. That is,the human anatomy of the cervical spine may be such that the lateralmass of the facet joints are not perpendicular to the surface of thefacet joint. Additionally, to properly place the forks 1012 of thedelivery device 1004 within the joint, the delivery device 1004 may bepositioned substantially parallel to articular surfaces of the facetjoint. As such, the delivery device 1004 may not be positionedperpendicular to the lateral masses of the facet joints and may actuallybe directed with a downward slope as it extends in the distal direction.Where the decorticator 1006 has an non-chamfered annular end, dependingon anatomy, the decorticator 1006 may be able to be placed in contactwith the superior lateral mass, but may be unable to reach or contactthe inferior lateral mass. In the present embodiment, the chamfered endof the tubular shaft portion 1034 will allow the distal tip of thechamfered end to reach and decorticate the inferior lateral mass. Thischamfered distal end may define an angle to the longitudinal axis. Insome embodiments this angle may range from approximately 10 degrees toapproximately 80 degrees. In other embodiments, this angle may rangefrom approximately 30 degrees to approximately 60 degrees. In otherembodiments, this angle may be approximately 45 degrees. Additionally,the teeth 1037 may be relatively large as shown in FIG. 124, or they mayrelatively small. Moreover, the teeth 1037 may extend along the fullperimeter surface of the chamfered end rather being positioned solely atthe tip of the chamfered end.

Additionally shown in FIG. 124 is a beveled edge 1039 along theperiphery of the chamfered end. That is, along the ovular shape createdby the chamfered tubular shaft portion 1034, the edge is beveled. Assuch, when the delivery device 1004 is inserted into the patient and/orwhen the decorticator 1006 is advanced along the delivery device 1004,the beveled edge 1039 may assist in avoiding tissue snags and thedecorticator 1006 may be placed in contact with the lateral mass of thefacet joints in a much smoother process and may avoid damage toneighboring tissues.

The handle 1038 of the decorticator 1006 may include a generallycylindrically shaped knob with a gripping surface along its peripheraledge and may sleevably receive the tubular shaft portion 1034. Thehandle 1038 may also include radially extending bores 1041 adapted toreceive the gripping tool 1001. The bores 1041 may extend from the outersurface of the handle radially inward and end at the outer surface ofthe tubular shaft portion 1034. As such, one or several gripping tools1001 may be inserted into any one or several of the bores 1041 in thehandle 1038 and may provide for better control and a higher amount oftorsional leverage when decorticating the lateral masses of the facetjoint. Additionally, the gripping tool 1001 extending laterally from thehandle 1038 may allow for malleting in the longitudinal direction of thedecorticator 1006. That is, the gripping tool 1001 may be inserted intothe bore 1041 and the decorticator 1006 may be advanced to contact thelateral mass of the facet joint. A mallet may be used to strike the sideof the gripping tool 1001 to cause forceful decortication of the lateralmass. The decorticator may then be retracted, rotated to a new radialposition, advanced, and struck again for additional decortication. Insome embodiments, the handle 1038 may be shaped relatively oblong so asto provide a mass of material that extends laterally away from thelongitudinal axis of the decorticator 1006. In this embodiment, the bore1041 may not be a radial bore 1041, but may be offset from the passingthrough the center point of the decorticator 1006 a distance equal to orgreater than a radius of the tubular shaft portion 1034. As such, thebore may pass all the way through the handle without encountering thetubular shaft 1034. Accordingly, the gripping tool may be inserted intothe bore 1041 and extended all the way through the handle 1038, allowingfor additional ability to grip and/or mallet the gripping tool 1001 andmanipulate the decorticator 1006.

In still another embodiment, the bores 1041 may be positioned on thedistal face of the handle 1038. In this embodiment, the bores mayreceive the gripping tool 1001, the tool being oriented parallel to thelongitudinal axis of the decorticator 1006 and allowing for malletingthe proximal end of the gripping tool 1001 to decorticate the lateralmass. In still another embodiment a series of gripping tools 1001 may beinserted into a series of bores 1041 positioned on the distal face ofthe handle 1038, each available to be used for malleting or manipulatingthe decorticator 1006. In still another embodiment, a single malletingtool (not shown) may be included, which has a series of longitudinallyextending rods each receivable by a series of bores 1041 on the distalface of the handle 1038. At a positioned proximal to the receivingassembly 1010 of the delivery device 1004, the series of rods mayconverge to a centrally positioned malleting surface. As such, thismalleting surface may be used to mallet the decorticator 1006 allowingfor the force of the mallet to be positioned along the longitudinal axisof the decorticator.

Additionally shown in FIG. 124 is a radially extending threaded bore1047 adapted to receive a corresponding threaded set screw. Thisthreaded bore 1047 may extend from the outer surface of the handle 1038radially inward through the wall of the tubular shaft portion 1034allowing access to the tubular shaft 1014 of the delivery device 1004.The set screw may be advanced through the handle 1038 to engage thedelivery device 1004 and prevent the decorticator 1006 from advancing ortwisting inadvertently. As mentioned and shown in FIG. 123, the deliverydevice 1004 may include a groove 1021 on the outside surface of thetubular shaft 1014 for receiving the tip of the set screw or otherwisecreating a catch point for the decorticator. As such, when thedecorticator 1006 is in its fully retracted and most proximal position,the threaded bore 1047 and set screw may align with the groove 1021 inthe tubular shaft 1014 and thus hold the decorticator 1006 in its mostproximal position. The set screw may be a thumbscrew-type with a headthat includes longitudinally extending ribs around its periphery forpurposes of gripping the screw. Alternatively the head may be a wing nuttype head for ease of setting and unsetting of the screw. In stillanother embodiment, the decorticator may have a relatively snug frictionfit at the proximal end that engages the groove 1021 when retracted. Instill another embodiment, the tubular shaft portion 1034 of thedecorticator may include a protruding rib on its inside surface adaptedto engage the groove 1021 on the tubular shaft 1014. A key slot 1049extending transversely across the threaded bore 1047 may also beprovided. Additional features of the decorticator 1006 may includefeatures of other decorticators shown and described herein. For example,the decorticator 1006 may alternatively be separate from the deliverydevice 1004 and may be slidably inserted within the delivery device 1004similar to that shown and described with respect to FIG. 4 or FIGS.6A-6C.

Referring now to FIG. 125, the driver assembly 1042 is shown. As shown,the driver assembly 1042 includes a handle 1044, an implant shaft 1046,and implant holding arms 1048.

The implant shaft 1046 may have an outer radius substantially equal tothe inner radius of the tubular shaft portion 1014 of the deliverydevice 1004 (shown in FIG. 123) allowing for slidable insertion of thedriver assembly 1042 within the delivery device 1004. Alternatively, theouter radius of the implant shaft 1046 may be smaller than the innerradius of the tubular shaft 1014 providing for more play andadjustability of the driver assembly 1042 and delivery device 1004relative to one another. In some embodiments the implant shaft 1046 mayhave a radius ranging from approximately 1 mm to approximately 8 mm. Inother embodiments, the implant shaft 1046 may have a radius ofapproximately 4 mm.

The handle 1044 of the driver assembly 1042 may have an outer surfacedefining a volume with a bore 1043 extending there through. The bore1043 may have an inner diameter substantially equal to the innerdiameter of the implant shaft 1046 allowing for a smooth transition ofdevices passing through the driver assembly 1042. The handle 1044 mayhave a generally rectangular shape at its distal end corresponding tothe proximal end of the receiving assembly 1010. The handle 1044 mayinclude gripping slots 1051 near its distal end to aid users with glovesin securely holding the driver assembly 1042. Additionally, these slots1051 may aid a user in hold the assembly 1042 with a hemostat or othergripping device. Additionally, the handle 1044 may have a necked downportion 1045 at its distal end in the form of one or more projections.In one embodiment, the necked down portion 1045 may have protrusions orrecesses (not shown) on its outer surface corresponding to respectiveprotrusions or recesses on the inner surface of the shell 1015 of thereceiving assembly 1010 on the delivery device 1004. As such, the driverassembly 1042 may be sleevably positioned within the delivery device1004 to deliver an implant to the facet joint. When fully advanced,similar to that shown in FIG. 101, the handle 1044 may be seatedsecurely in the seating cavity 1013 of the receiving assembly 1010.Where protrusions are included on the necked down portion 1045 andrecesses are included on the inner surface of the shell 1015, the handlemay be anchored with a detent relationship. The projections of thenecked down portion 1045 of the handle 1044 may correspond to theseating cavities 1013 of the receiving assembly. Additionally, theseprojections may taper as they extend distally to provide a friction typefit into the seating cavities 1013 of the receiving assembly 1010.

The seating relationship provided by necked down portion 1045 of thedriver assembly 1042 and the receiving assembly 1010 of the deliverydevice 1004 may allow the user to control the placement of the implantin both a longitudinal and a rotational direction. That is, once theanchoring forks 1012 of the delivery device 1004 are properly placed inthe facet joint, proper placement of the driver assembly 1042 may thenbe ensured by aligning and seating the handle 1044 of the driverassembly 1042 in the receiving assembly 1010 of the delivery device1004. Thus, the seating relationship may prevent the driver assembly1042 from being inserted too far and may also allow the driver assembly1042 to be aligned with the delivery device 1004 rotationally to ensureproper rotational orientation of the implant. Additional features of thedriver assembly 1042 may include those features shown and described withrespect to driver assembly 142.

The implant holding arms 1048 may include features similar to other armsshown and described herein. For example, the inside surface of the arms1048 may include a longitudinal ridge 1062 extending the length of thearms 1048. The arms 1048 may also include a bull nose engagement feature1058 extending transverse to the longitudinal axis of the implant shaftalong the inside face of the arm 1048. Where the arms 1048 are engagedwith and holding the implant, the longitudinal ridges 1062 of each arm1048 may be positioned between upper and lower planar members of theimplant and the bull nose engagement features 1058 may be positioned inthe U-shaped receiving feature slots on the lateral edges of theimplant.

In contrast to the driver assembly 142 and consistent with the driverassembly 842, each described above, in the present embodiment, theinternal actuator 1052 may be a separate device from the driver assembly1042. As shown in FIGS. 126, the internal actuator 1052 may include alongitudinal shaft 1055 a handle 1053, and an internal rod 1057 (notshown in FIGS. 126-126B). The longitudinal shaft 1055 may becylindrically shaped with an annular cross-section. The shaft 1055 mayhave an outer diameter substantially the same as or smaller than theinner diameter of the implant shaft 1046 of the driver assembly 1042.The shaft 1055 may extend from the handle 1053 proximally to a distalend. The internal actuator 1052 may be used in conjunction with theinternal rod 1057 positioned within the shaft 1055.

The internal rod 1057, shown separately in FIG. 127, may be positionedwithin the shaft 1055 and may extend from the handle 1053 to the distalend of the longitudinal shaft 1055. The internal rod 1057 may include anengagement feature 1059 at its distal end for engaging and holding theimplant distractor. This engagement feature 1059 may be any shape andprovide for any engagement known in the art from a hex, allen, phillips,star, square, sleeve, or other connection capable of transmittinglongitudinal and/or rotational forces from the internal rod 1057 to theimplant distractor. In one embodiment, the engagement feature 1059includes a collet type device that is described in more detail withrespect to FIG. 127A below.

The internal rod 1057 may sleevably receive the implant distractor. Theinternal rod 1057 may be sleevably positioned within the longitudinalshaft 1055, such that when the longitudinal shaft 1055 is in an advancedposition over the end of the internal rod 1057, the longitudinal shaft1055 causes a clamping force of the collet to restrain the implantdistractor against being dislodged from the collet. Each of the shaft1055 and the internal rod 1057 may engage the handle 1053 at theirrespective proximal ends and be affixed there to. The shaft 1055 may besecurely affixed to the handle 1053 such that rotational andlongitudinal motion of the handle 1053 imparts the same motion on theshaft 1055. In contrast, the internal rod 1057 may be slidably affixedto the handle 1053 such that rotational motion of the handle 1053imparts the same motion on the internal rod 1057, but longitudinalmotion of the handle 1053 is isolated from the internal rod 1057 via abiasing mechanism. As such, the handle 1053 may be used to retract thelongitudinal shaft 1055 along the length of the internal rod 1057thereby exposing the collet and reducing the clamping force on theimplant distractor, but when the handle 1053 is rotated, both thelongitudinal shaft 1055 and internal rod 1057 rotate with the handle1053. When the longitudinal shaft 1055 is in a retracted position, animplant distractor may be inserted into and/or removed from the colletdue to the reduced clamping force.

As shown in FIGS. 126A and 126B, the handle 1053 may be a generallycylindrical shape with a cone shaped distal end and a relatively flatproximal end. As shown, the proximal end of the handle 1053 may includea circumferential ridge 1051 projecting proximally and extending alongthe periphery of the cylindrical shape. The inner face of the ridge maybe braced by a plurality of radially spaced ribs 1061. The center of theproximal end may include a button 1063 covered by a flexible membrane1065, the proximal end of the button 1063 being recessed slightly fromthe circumferential ridge 1051, which protects the button 1063 againstinadvertent triggering when the handle 1053 is being used to twist orturn the implant distractor. As such, the handle 1053 shown may reducethe chance that the implant distractor will become dislodged or releasedfrom the engagement feature 1059 of the internal actuator 1052 prior tobeing fully advanced and fully distracting the implant.

As shown in the cross-section of the handle 1053 in FIG. 126B, thebutton may be held in position by an internal spring 1067 or otherbiasing mechanism or device and may also include longitudinal keywaysallowing for relative longitudinal motion of the button relative to thehandle 1053, but preventing relative rotational motion. In use, theimplant distractor may be placed in the engagement feature 1059 at thedistal end of the internal rod 1057 and the internal rod 1057 may be inposition inside the longitudinal shaft 1055. As mentioned above, in theembodiment, shown, when the internal rod 1057 has a collet typeengagement feature 1059, the retraction of the internal rod 1057 withinthe longitudinal shaft 1055 may cause a circumferential clamping forcefrom the longitudinal shaft 1055 onto the engagement feature 1059 of theinternal rod 1057, thereby securing the implant distractor in theengagement feature 1059 of the internal rod 1057. Once assembled, theinternal actuator 1052 may be inserted and advanced through the driverassembly 1042 positioning the implant distractor just proximal to theimplant being held by the implant holder arms of the driver assembly.The handle 1053 may then be rotated to cause the implant distractor toadvance into the implant thereby distracting the implant.

Once the implant distractor is fully advanced, the handle 1053 may begrasped and the button may be pressed, while pulling on the cone shapedportion of the handle 1053, which may counteract the biasing force ofthe spring 1067 or other biasing mechanism and cause relativelongitudinal motion between the internal rod 1057 and the longitudinalshaft 1055. Accordingly, the distal end of the internal rod 1057 mayextend beyond the distal end of the longitudinal shaft 1055 and theclamping force on the engagement feature 1059 may be removed allowingthe internal actuator 1052 to be removed leaving the implant distractorbehind.

As shown in more detail in FIGS. 127 and 127A, the engagement feature1059 at the distal end of the internal rod 1057 may take the form of acollet 1093 for holding the implant distractor. The collet 1093 may beaffixed to the distal end of the internal rod 1057 and may be adapted tohold the implant distractor. The collet 1093 may be permanently affixedto the distal end of the internal rod 1057 or may be interchangeablycoupled thereto. Several collet and chuck arrangements are known in thetool industry for receiving bits or other devices and are within thescope of the invention.

The collet 1093 may include any or all of the features of other colletsshown and described herein. For example, the collet 1093 may include agenerally cylindrical body member 1095 with four receiving fingers 1097equally spaced around a bore 1099. The collet 1093 may include as few astwo fingers 1097 and may include any number of fingers 1097.

In still another embodiment, a second internal actuator may be provided.This second internal actuator may include a handle securely affixed to ashaft and an engagement feature securely affixed to a distal end of theshaft. The engagement feature may correspond to the shape of theproximal end of the implant distractor. In one embodiment, this shape isa female square shape corresponding to a square shaped proximal end ofthe implant distractor. This engagement feature may include any shapeknown in the art as mentioned with respect to the engagement feature1059 discussed above. This second internal actuator may be used toadvance the implant distractor. For example, the second internalactuator may be used if the internal actuator 1052 were to lose its gripon the implant distractor. That is, if the collet loses its grip for anyreason including deformation of the fingers of the collet or due tomalfunction of the internal actuator 1052 for any reason, the secondinternal actuator may be used. The second internal actuator may bepassed down the tubular shaft 1046 of the driver assembly 1042 to engagethe proximal end of the implant distractor. The engagement feature onthe distal end of the second internal actuator may be brought intoengagement with the proximal end of the implant distractor and thesecond implant distractor may be used to rotate or otherwise advance theimplant distractor thereby distracting the implant.

Turning now to FIG. 128, an injector 1102 is shown. The injector 1102may include a longitudinal delivery shaft 1117, a seating feature 1119,and a plunger 1123 with a handle 1125. The longitudinal delivery shaft1117 may have any cross-section and may have a cross-sectional sizeadapted to fit within the delivery device 1004. The longitudinal shaft1117 may have an opening 1127 on its distal end for directing bone pasteout the distal end of the shaft 1117 allowing the paste to flow intoand/or over the facet joint and/or outward toward the lateral mass of afacet joint. The seating feature 1119 may include a rectangular or othershaped block positioned around the shaft 1117, which may be sized andshaped to abut the receiving assembly 1010 of the delivery device 1004.As with the driver assembly 1042, the distal end of the seating feature1119 may have a shape corresponding to the shape of the proximal end ofthe receiving assembly 1010. As shown, this is a generally rectangularshape, but may be any shape. Additionally, the seating feature 1119 mayinclude gripping slots 1027 nears its distal end. Additionally, theseating feature 1119 may include a necked down portion 1025 on itsdistal end which may be received by the seating cavities 1013 of thereceiving assembly 1010. As with the driver assembly 1042, the seatingfeature 1119 of the injector 1102 may include protrusions or recesses(not shown) corresponding to protrusions or recesses on the innersurface of the shell 1015 allowing for a detent relationship forsecuring the injector 1102 to the delivery device 1004.

The injector 1102 may be sleevably inserted into the delivery device1004 and advanced such that the distal end of the shaft 1117 ispositioned between the forks 1012. The plunger handle 1125 may bepressed distally and bone paste or other material may be injected towardthe facet joint site. Additional features not mentioned may be includedas shown and described with respect to the injector 202 and/or 902. Forexample, the plunger 1123 may include a seal.

A gripping tool 1001 has been referenced for use with several of theabove devices, including, but not limited to the chisel 1008 and thedecorticator 1006. As shown in FIG. 121, the gripping tool 1001 mayinclude a shaft 1003 and a handle 1005. The shaft 1003 may be made of arelatively rigid material and may have a diameter adapted to fit intothe bores provided in the chisel 1008 and the decorticator 1006. Thehandle 1005 of the gripping tool 1001 may be any shape. In oneembodiment, the handle 1005 is a T-type handle 1005. In antherembodiment, as shown, the handle 1005 is a spherically shaped handle1005. The handle 1005 may be adapted in size and shape to nest in thepalm of a human hand and such that it can be used to push, pull, orrotate the devices it is connected to or be struck with a mallet.

Referring now to FIGS. 129-135B, a dilator set 1200 is shown. FIGS.129-131 show an assembled set of dilators including a dilator rod 1202and a plurality of dilator sleeves 1204, including a small 1204A, medium1204B, and large 1204C dilator. Any number of dilator sleeves 1204 maybe included. Each of the dilator sleeves 1204 may have an inner diametercorresponding to the outer diameter of the next smallest sleeve, thesmallest sleeve 1204A having an inner diameter corresponding to theouter diameter of the dilator rod 1202. Each of the dilator sleeves 1204and dilator rod 1202 may have varying lengths, the largest of thesleeves 1204C having the shortest length, the dilator rod 1202 havingthe longest length, and the other sleeves 1204A, 1204B having lengthsthere between, such that each rod 1202 or sleeve 1204 is longer than thenext largest sleeve. Each of the dilator rods 1202 and sleeves 1204 mayinclude a tapered tip.

As shown in FIGS. 132 and 132A, the dilator rod 1202 is shown. Thedilator rod 1202 may be a generally solid shaft or may include aninterior lumen for receiving a guide wire. The rod 1202 may have anyouter diameter. In one embodiment, the rod 1202 has an outer diameter ofbetween approximately 1 mm and 5 mm. In another embodiment, the rod 1202has an outer diameter of approximately 3 mm. The rod 1202 may have anylength. In one embodiment, the rod 1202 has a length of betweenapproximately 200 mm and 400 mm. In another embodiment, the rod 1202 hasa length of approximately 290 mm. The tip of the rod 1202 may be taperedand may further include a radiused distal tip. As such, the tip may beadapted to penetrate and dilate tissue.

FIGS. 133, 133A, and 133B show the small dilator sleeve 1204A. The smallsleeve 1204A may have an inner diameter adapted to slide over thedilator rod 1202. The inner diameter of the small sleeve 1204A may beonly slightly larger than the rod diameter or may be much larger. In oneembodiment, the inner diameter of the small sleeve 1204A is 0.6 mmlarger than the dilator rod diameter. The small sleeve 1204A may haveany outer diameter and any length. In one embodiment, the small sleeve1204A has an outer diameter of between approximately 3 mm and 9 mm. Inanother embodiment, the small sleeve 1204A has an outer diameter ofapproximately 6 mm. In one embodiment, the small sleeve 1204A has alength of between approximately 200 mm and 300 mm. In anotherembodiment, the small sleeve 1204A has a length of approximately 260 mm.The small sleeve 1204A may include a tapered tip with a radiused distaledge and, as such, the small sleeve may be adapted to slide over thedilator rod and further dilate tissue.

FIGS. 134 and 134A and FIGS. 135, 135A, and 135B, show a medium dilatorsleeve 1204B and a large dilator sleeve 1204C respectively. The mediumsleeve 1204B may have an inner diameter adapted to slide over the smallsleeve 1204A and the large sleeve 1204C may have an inner diameteradapted to slide over the medium sleeve 1204B. Each of the medium sleeve1204B and large sleeve 1204C may have an inner diameter only slightlylarger than the outer diameters of the small 1204A and medium 1204Bsleeve respectively or they may have an inner diameter that is muchlarger. In one embodiment, the medium sleeve 1204B and the large sleeve1204C may have an inner diameter that is approximately 0.6 mm largerthan the outer diameter of the small sleeve 1204A and the medium sleeve1204B respectively. The medium sleeve 1204B may have any outer diameterand any length. In one embodiment, the medium sleeve 1204B has an outerdiameter of between approximately 4 mm and 12 mm. In another embodiment,the medium sleeve 1204B has an outer diameter of approximately 8 mm. Inone embodiment, the medium sleeve 1204B has a length of betweenapproximately 180 mm and 280 mm. In another embodiment, the mediumsleeve 1204B has a length of approximately 230 mm. The large sleeve1204C may also have any outer diameter and any outer length. In oneembodiment, the large sleeve 1204C has an outer diameter of betweenapproximately 6 mm and 18 mm. In another embodiment, the large sleeve1204C has an outer diameter of approximately 11 mm. In one embodiment,the large sleeve 1204C may have a length of between approximately 150 mmand 250 mm. In another embodiment, the large sleeve 1204C may have alength of 200 mm. Each of the medium 1204B and large 1204C sleeves mayinclude a tapered tip with a radiused distal edge. As such, each of themedium 1204B and large 1204C sleeves may be adapted to dilate tissueslightly more than the corresponding smaller sleeve.

In use, the dilator set of FIGS. 129-135B may be used to dilate tissuesto access a facet joint. That is, once an incision is made, the dilatorrod 1202 may be advanced alone or over a guidewire through the tissuesof the back up to and/or into the facet joint. Once the rod 1202 is inposition, the small sleeve 1204A may be advanced over the rod 1202 fromthe proximal end of the rod 1202 and may be advanced along the fulllength of the rod 1202. The longer length of the rod 1202 may allow therod 1202 to extend out of the proximal end of the small sleeve 1204Asuch that control of both elements of the dilator set are maintained.The small sleeve 1204A may be advanced fully such that the tip of thesmall sleeve 1204A is flush with the tip of the rod 1202, thus dilatingthe tissues in an amount equal to the outer diameter of the small sleeve1204A. This process may continue with larger and larger sleeves 1204 toappropriately dilate the tissues and allow access to the facet joint.Depending on the dilation necessary, the order and type of dilation mayvary. That is, in some instances, the rod may not be necessary. In otherinstances, some of the sleeves may be omitted or skipped.

The above description has included some references to use to allow for abetter understanding of the structure. Below is a more detaileddiscussion of that use including the devices and techniques fordistracting and retaining a facet joint in a distracted and forwardlytranslated condition. The implantation procedure may be performed underconscious sedation in order to obtain intra-operative patient symptomfeedback.

The joint, which is difficult to access, may be accessed pursuant, forexample, to a method and apparatus disclosed in U.S. Non-provisionalapplication Ser. No. 61/350,609, filed Jan. 8, 2009, which is commonlyowned with the present application and hereby incorporated by reference.Pursuant to the disclosure in that application, the access system mayinclude one or more cannulas made of steel, titanium, or plastic. Theinitial facet joint access cannula may have a sharp spatula tip on thedistal end. The spatula tip may have a flat configuration to enableaccess into the flat facet joint. Once the spatula tip achieves accessinto the flatly oriented facet joint, subsequent stylets and workinginstruments may be passed down this access channel to complete adistraction procedure. Alternatively the dilation set 1200 may be used.Alternatively, one or a plurality of the chisel and delivery devicesdescribed above may be used to access the joint. The distractionprocedure may then begin.

More particularly, initially, an incision may be made in the patientsback. Tools known in the art may be used to create this incision and thedilator set 1200 may be used to open an access path through the tissuesof the back as described above. Once an access path is created, thechisel 1008 described above may be advanced through the incision and thedistal tip 1030 may be positioned adjacent the target facet joint. It isnoted that chisel 1008 with an interior lumen may allow forvisualization to be provided by including a scope within the chisel1008. Additionally, an incision in the facet joint capsule may be madeprior to beginning the procedure, and thus prior to insertion of thechisel 1008. Once the distal tip of the chisel 1008 is properlypositioned adjacent the facet joint, the chisel 1008 may be insertedinto the facet joint. The chisel 1008 may be used to decorticate thearticular surfaces of the facet joint by manipulating the chisel 1008within the joint. This may include tapping the chisel with a device suchas a hammer, mallet, or other instrument to advance the distal tip 1030of the chisel 1008 and may also include moving the proximal end of thechisel laterally from side to side, up and down, or rotationally, todecorticate the joint. The chisel may then be tapped into placeanteriorly such that it extends substantially through the joint.Fluoroscopy from one or more directions may be used to verify thelocation of the chisel.

The delivery device 1004 may be slidably advanced over the chisel 1008such and the forks 1012 of the delivery device 1004 may be advanced intothe facet joint. Additional fluoroscopy from one or more directions maybe used to verify proper placement of the delivery device 1004 and forks1012. The chisel 1008 may be removed.

An implant may be placed in the driver assembly 1042 and the implant anddriver assembly 1042 may be slidably advanced through the deliverydevice 1004. The forks 1012 of the delivery device 1004 may be holdingthe facet joint slightly distracted. As such, the implant, in itsrelatively flat and parallel position, may slide relatively easily intothe facet joint. To the extent that it does not, the proximal end of thedriver assembly 1042 may be tapped to properly advance and position theimplant.

The button on the handle 1053 of the internal actuator 1052 may bepressed to expose the engagement feature 1059 at the distal end of theinternal rod 1057 of the internal actuator 1052 and the implantdistractor may be placed therein. The button may be released causing atleast the proximal end of the implant distractor and the engagementfeature 1059 to be retracted within the longitudinal shaft 1055 of theinternal actuator 1052 thereby causing a clamping force on theengagement feature 1059 and securing the implant distractor.

The internal actuator 1052 may then be inserted into the proximal end ofthe driver assembly 1042 and advanced to a point just proximal to theimplant. Once properly positioned, the handle 1053 may be rotated orotherwise actuated to advance the implant distractor into the implantthereby distracting implant and the facet joint.

The button on the handle 1053 may be pressed again to expose theengagement feature 1059 at the distal end of the internal rod 1057 fromthe longitudinal shaft 1055 thereby reducing the clamping force of theengagement feature on the implant distractor and allowing for removal ofthe internal actuator, while the implant distractor is threadablyengaged with the implant. Additionally, the distraction of the implantmay cause the upper and lower members of the implant to clear theengagement features 1058 of the holder arms 1048 thus allowing thedriver assembly 1042 to be freely removed from the delivery device 1004leaving the implant and the implant distractor behind.

The injector 1102 may be advanced through the delivery device 1004 andpositioned adjacent to the facet joint. The handle 1025 of the plunger1023 may be depressed thus advancing the plunger 1023 and ejecting thebone paste or other anchoring material. The injector 1102 may beremoved. The delivery device 1004 may also be removed and the incisionmay be closed. The above procedure may be conducted to treat one or bothcontralateral facet joints.

In still another embodiment, a chisel 2008 may include a handle 2044 thesame or similar to the handle 1044 on the driver assembly 1042. In thisembodiment, the chisel 2008 may be engaged with the delivery device 1004via a connection between the handle 2044 and the receiving assembly 1010and both the chisel 2008 and the delivery device 1004 may be introducedinto the facet joint at the same time allowing for a one-step process ofinitially entering the facet joint rather than initially entering thejoint with the chisel 1008 and then passing the delivery device 1004over the chisel 1008. Once the chisel 2008 and the deliver device 1004are properly positioned, the chisel 2008 may be removed.

In another embodiment, upon placement of the chisel 2008 and thedelivery device 1004 in a first facet joint, the chisel 2008 may beremoved and replaced with a radiolucent chisel as a place holder. Thedelivery device 1004 may also be removed and reassembled with the chisel2008. The delivery device and chisel 2008 may then be inserted into thecontralateral facet joint or second joint. By replacing the chisel 2008in the first joint with a radiolucent chisel, the positioning of thechisel 2008 and delivery device 1004 may be more readily ascertainableusing lateral fluoroscopy. That is, if a radiopaque chisel or deliverydevice was left in place in the first joint, the fluoroscopic view ofthe contralateral facet joint would be relatively occluded. Upon placingthe delivery device 1004 properly in the second facet joint, theprocedure above may continue. Upon completing treatment of the secondfacet joint, the delivery device 1004 may be sleeved over theradiolucent chisel holding the place in the first facet joint and thefirst facet joint may then be treated with the above procedure.

In another embodiment, a tool 2000 may include some or all of theelements described with respect to, tool 1000. However, the driverassembly 1042 may be omitted. In this embodiment, delivery of theimplant may be conducted with the internal actuator 1052. That is, theimplant distractor may be initially partially engaged with or “started”in the implant sufficiently to hold the two together. This engagementmay be due to the implant being biased to keep the upper and lowermembers in a parallel position thus creating a threaded and frictionalresistance to separation of the implant and the implant distractor.Additionally or alternatively, this engagement may be due to engagementof a cross-cut thread on the implant distractor being engaged with atruncated threaded slot of the implant. Once the implant distractor isstarted in the implant, the implant distractor may be engaged with theengagement feature on the internal actuator 1052 thus stringing theinternal actuator 1052, the implant distractor, and the implanttogether. The internal actuator 1052 together with the implantdistractor and the implant may then be advanced down the tubular shaft1014 of the delivery device 1004 in lieu of the driver assembly 1042.

In this embodiment, the omission of the driver assembly 1042 may allowfor smaller sized shafts of several devices. In one embodiment, theouter radius of the tubular shaft 1014 of the delivery device 1004 maybe approximately 4 mm and the outer radius of the decorticator may beapproximately 5 mm.

In still another embodiment, the several handles (e.g., 1044, 2044,1119) may include a slot opening on their distal end for use inseparating the handles from the receiving assembly 1010. That is, whenthe handles are engaged with the receiving assembly and the projectionsare seated in the seating cavities, the frictional/suctional fit of thehandles in the receiving assembly may be difficult to separate.Accordingly, a slot opening on the distal end of the handles may beprovided, which may provide for accessing the joint between the handlesand the receiving assembly with a separation device which may assist inworking the elements apart via prying, scissor action, or other knownmethods. Alternatively or additionally, the frictional engagement of theseveral handles in the receiving assembly may be reduced.

The delivery system disclosed herein is advantageous for at least thefollowing reasons. First, the system facilitates delivery of an implantto a facet joint via a minimally invasive or percutaneous procedure,reducing the risk, surgical time and recovery time associated with theimplantation of the implant in the facet joint. Accordingly, many of thedimensional characteristics associated with the delivery system, itscomponents, and the implant are advantageous in that they facilitate ormake possible the minimally invasive or percutatneous proceduresdescribed herein. Second, the system facilitates the implant beingdelivered while the patient is capable of providing verbal feedback asto the impact of the implant relative to symptoms being felt by thepatient.

Although the present invention has been described with a certain degreeof particularity, it is understood the disclosure has been made by wayof example, and changes in detail or structure may be made withoutdeparting from the spirit of the invention as defined in the appendedclaims.

1. A spinal joint distraction system comprising: a delivery deviceincluding: a tubular shaft; a receiving assembly positioned on aproximal end of the tubular shaft and including a seating cavity; and apair of forks extending from a distal end of the tubular shaft, theforks adapted to penetrate a facet joint; a chisel including a shaftwith a chamfered tip, the chisel being adapted for slidable insertionthrough the delivery device; a decorticator sleevably positioned on thetubular shaft of the delivery device, the decorticator comprising: atubular shaft portion with a chamfered distal end; a plurality ofserrated teeth at the distal tip of the chamfered end; a beveled edgeextending along the periphery of the chamfered distal end; and a handlepositioned on the proximal end of the tubular shaft portion, the handlehaving a bore adapted to receive a gripping tool and a threaded bore forreceiving a set screw; a driver assembly adapted for slidable insertionthrough the delivery device, the driver assembly comprising: an implantshaft; a handle positioned on the proximal end of the implant shaft; andimplant holding arms extending from the distal end of the implant shaft;an internal actuator adapted for slidable insertion through the driverassembly and further adapted to advance an implant distractor, theinternal actuator comprising: a longitudinal shaft; a handle positionedon the proximal end of the longitudinal shaft and adapted to rotatablyadvance the implant distractor; and an internal rod including anengagement feature adapted to secure the implant distractor; and aninjector adapted for slidable insertion through the delivery device, theinjector comprising: a longitudinal delivery shaft; a seating featurepositioned around the shaft; and a plunger adapted to pass through thelongitudinal delivery shaft causing ejection of material from the distalend of the longitudinal delivery shaft.
 2. The system of claim 1,wherein the implant holding arms of the driver assembly include anengagement feature for engaging a lateral portion of an implant.
 3. Thesystem of claim 2, wherein the engagement feature includes a tabstructure.
 4. The system of claim 2, wherein the engagement featureincludes a bull nose feature adapted to engage a U-shaped slot.
 5. Thesystem of claim 1, wherein the internal actuator is rotatably engagedwith the implant distractor via the internal rod.
 6. The system of claim1, wherein the engagement feature of the internal rod is a collet. 7.The system of claim 1, wherein the driver assembly further comprises anecked down portion adapted to seat within the seating cavity of thedelivery device.
 8. The system of claim 1, wherein the injector furthercomprises a necked down portion adapted to seat within the seatingcavity of the delivery device.
 9. The system of claim 1, wherein thechisel includes a longitudinal lumen.
 10. The system of claim 1 furthercomprising a gripping tool adapted to engage a bore on the chisel or thedecorticator.
 11. A spinal joint distraction system comprising: adelivery device with a decorticator sleevably positioned thereon; achisel adapted for insertion through the delivery device; a driverassembly adapted for insertion through the delivery device and furtheradapted to hold an implant; an internal actuator adapted for insertionthrough the driver assembly and adapted to deliver and advance animplant distractor thereby distracting the implant; and an injectoradapted for insertion through the delivery device and further adapted todeliver flowable material to or around the joint.
 12. The system ofclaim 11, wherein the chisel comprises: a shaft; a chamfered tip at thedistal end of the shaft; a coped end at the proximal end of the shaft;and a horizontal bore passing through the distal end of the shaft, thebore adapted to receive a gripping tool.
 13. The system of claim 12,wherein the chamfered tip has a roughened surface for decorticatinginner surfaces of the joint.
 14. The system of claim 13, wherein thechamfered tip has a length from approximately 11 mm to approximately 17mm.
 15. The system of claim 11, wherein the delivery device comprises: atubular shaft; a receiving assembly positioned on a proximal end of thetubular shaft and including a seating cavity; and a pair of forksextending from a distal end of the tubular shaft, the forks adapted topenetrate a facet joint.
 16. The system of claim 15, wherein the tubularshaft includes a circumferential groove just distal to the receivingassembly.
 17. The system of claim 15, wherein the forks have a roughenedsurface for decorticating the inner surfaces of the joint and foranchoring the delivery device in the joint.
 18. The system of claim 17,wherein the forks have a length from approximately 11 mm toapproximately 17 mm.
 19. The system of claim 15, wherein the receivingassembly includes a bore in alignment with the tubular shaft, the borehaving a tapered entrance.
 20. The system of claim 11, wherein thedecorticator includes a handle with a bore adapted to receiving agripping tool.
 21. The system of claim 20, wherein the handle furthercomprises a threaded bore for receiving a set screw.
 22. The system ofclaim 11, wherein the decorticator includes a tubular shaft portion witha chamfered and beveled distal end and further includes serrated teethon the distal tip of the distal end.
 23. The system of claim 11, whereinthe internal actuator includes a handle with a recessed button.
 24. Thesystem of claim 23, wherein the handle of the internal actuator includesa biasing mechanism adapted to resist depressing the button.
 25. Thesystem of claim 23, wherein the internal actuator includes an internalrod with a collet for holding the implant distractor.
 26. The system ofclaim 11, further comprising a dilator set.
 27. The system of claim 26,wherein the dilator set includes a dilator rod and a plurality ofdilator sleeves.
 28. A spinal distraction implant comprising: an uppermember and a lower member each with a distal end, the distal end of thelower member coupled to the distal end of the upper member; and animplant distractor adapted to be advanced between the upper and lowermember and separate the upper and lower members causing the upper andlower member to pivot relative to one another about their respectivedistal ends.
 29. The implant of claim 28, wherein the upper and lowermember each further comprise a threaded slot and the implant distractorcomprises a coil shaped thread feature, each of the threaded slotsadapted to receive the coil shaped thread feature.
 30. The implant ofclaim 29, wherein the upper and lower member each further comprise atruncated threaded slot and the implant distractor comprises a cross-cutthread for engaging the truncated threaded slot and preventing theimplant from backing out.
 31. The implant of claim 28, wherein the uppermember and the lower member each further comprise an interlockingscissor feature and the upper and lower member are pivotally coupled viatheir respective interlocking scissor features.
 32. The implant of claim28, wherein the upper member and the lower member each comprise twolater edges and a plurality of teeth spaced along the two lateral edges.33. The implant of claim 28, wherein the upper member and the lowermember each comprise a guide feature for receiving and guiding theimplant distractor.
 34. A spinal distraction implant comprising: anupper member and a lower member each comprising: a distal edge, aproximal edge, and two parallel lateral edges, the edges defining agenerally rectangular shape; an inner surface; an outer surface; athreaded slot passing through the member from the inner surface to theouter surface; a truncated threaded slot passing through the member fromthe inner surface to the outer surface; a plurality of teeth spacedalong the two parallel lateral edges; a guide feature positioned on theproximal edge; and an interlocking scissor feature positioned on thedistal edge; and an implant distractor comprising: a cylindrical bodytapering to a point at a distal end; a coil shaped thread feature havingan abrupt proximal end and being interrupted by at least one cross-cut;and an annular stop ring; wherein the upper and lower members arepivotally coupled to one another via their respective interlockingscissor features; the respective guide features on the upper member andthe lower member oppose one another and are adapted to receive and guidethe distal end of the implant distractor between the upper and lowermembers; the respective threaded slots on the upper and lower member areadapted to receive the coil shaped thread feature; and the respectivetruncated threaded slots are adapted to engage the abrupt proximal endor the at least one cross-cut of the coil shaped thread feature.
 35. Theimplant of claim 34, wherein the plurality of teeth have a linearlysloped distal face and a proximal face positioned orthogonally to therespective upper or lower member.
 36. The implant of claim 35, whereinthe lateral edges of the upper and lower members follow a first radiusedcurve from the inner surface to the outer surface, wherein the extensionof the first radiused curve beyond the outer surface of the upper orlower member defines an outside face of the teeth.
 37. The implant ofclaim 36, wherein an inside face of the teeth is defined by a secondradiused curve offset from the first radiused curve such that theplurality of teeth have a substantially constant thickness.
 38. Theimplant of claim 37, wherein the teeth are equally spaced.
 39. Theimplant of claim 34, wherein the implant distractor includes a squareproximal end adapted to be received by a collet.
 40. The implant ofclaim 39, wherein the square proximal end further comprises acircumferential groove.
 41. The implant of claim 34, wherein therespective guide features each comprise a half-conical feature.
 42. Theimplant of claim 34, wherein the distal edges are further coupledtogether via a weld.
 43. A method of distracting a facet joint of thespine comprising: dilating a path to a facet joint using a dilator set;inserting a chisel into the facet joint; advancing a delivery deviceover the chisel and inserting forks of the delivery device into thefacet joint; removing the chisel from the joint; inserting a driverassembly with an implant into the delivery device, seating the driverassembly in the delivery device thereby positioning the implant betweenthe forks of the delivery device and in the facet joint; inserting aninternal actuator into the driver assembly and advancing an implantdistractor into the implant thereby distracting the implant; actuating abutton on the internal actuator thereby releasing a grip on the implantdistractor and removing the internal actuator and the driver assembly;and inserting an injector and injecting a flowable material into oraround the facet joint.
 44. The method of claim 43, wherein advancingthe implant distractor includes turning a handle on the internalactuator thereby rotating an internal rod and threadably advancing animplant distractor.
 45. A method of distracting a facet joint of thespine comprising: inserting a chisel into a facet joint to provideinitial distraction and decorticate the surface of the joint; insertinga delivery device over the chisel to maintain the initial distraction;inserting an implant through the delivery device and into the joint, theimplant having teeth adapted to engage the surfaces of the joint;distracting the implant by advancing an implant distractor, the implantdistractor having a coil-shaped thread feature for engaging threadedslots of the implant, the implant distractor further having cross-cutthreads for engaging truncated threaded slots on the implant, wherein,advancing the implant distractor includes causing the cross-cut threadsto engage the truncated threaded slots and prevent backing out of theimplant; and releasing the implant distractor and removing the deliverydevice thereby leaving the implant and the implant distractor in placein the joint.
 46. A spinal joint distraction system comprising: adelivery device; a driver assembly adapted for insertion through thedelivery device and further adapted to hold an implant; and an internalactuator adapted for insertion through the driver assembly and adaptedto deliver and advance an implant distractor thereby distracting theimplant.
 47. A spinal joint distraction system comprising: a driverassembly adapted to hold an implant; and an internal actuator adaptedfor insertion through the driver assembly and adapted to deliver andadvance an implant distractor thereby distracting the implant.
 48. Aspinal joint distraction system comprising: an implant; an implantdistractor adapted to engage the implant; and an internal actuatoradapted to advance the implant distractor thereby distracting theimplant.
 49. A method of distracting a facet joint of the spinecomprising: inserting a delivery device into a facet joint; inserting animplant through the delivery device and into the joint; and distractingthe implant by advancing an implant distractor.
 50. A method ofdistracting a facet joint of the spine comprising: partially engaging animplant distractor with an implant and engaging the implant distractorwith an internal actuator to form an assembly; inserting the implantportion of the assembly into the facet joint; and distracting the facetjoint.
 51. The method of claim 50, wherein distracting facet jointincludes actuating the internal actuator which advances the implantdistractor.
 52. A spinal distraction implant comprising an upper memberand a lower member each with a distal end, the distal end of the lowermember coupled to the distal end of the upper member, wherein the uppermember and lower member each comprise a plurality of threaded slotsadapted to engage an implant distractor.
 53. The implant of claim 52,wherein the plurality of threaded slots on the upper member or the lowermember further comprises a truncated threaded slot.
 54. The implant ofclaim 53, wherein the plurality of threaded slots on the upper memberand the lower member each comprises a truncated threaded slot.
 55. Aspinal distraction implant comprising an upper member and a lower membereach with a distal end, the distal end of the lower member including aninterlocking scissor feature coupled to a corresponding interlockingscissor feature included on the distal end of the upper member.
 56. Aspinal distraction implant comprising an upper member and a lowermember, each with a distal end, the distal end of the lower membercoupled to the distal end of the upper member, wherein the implant isadapted to receive an implant distractor between the upper and lowermember.
 57. The implant of claim 56, further comprising a guide featurepositioned on a proximal end of the upper member and the lower member.58. A spinal distraction implant comprising an upper member and a lowermember, the upper member and lower member coupled at respective distalends, the upper and lower members being biased toward a positionparallel to one another.
 59. The spinal distraction implant of claim 58,further comprising an implant distractor adapted to be advanced betweenthe upper and lower member and force the upper and lower member apartand counter to the biased position.